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Hardware

Better Power Supply Roundup 196

CainX writes "A comparison of five power supply units was posted recently. Anandtech has done a more complete review and examined 18 of the newest models in the plus 300 watt range." Power supplies tend to be one of those forgotten, but ever so important parts of machine construction.
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Better Power Supply Roundup

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  • by Anonymous Coward on Monday August 11, 2003 @08:47AM (#6664607)


    The dude writes that the 204W at 12V isn't enough for a P4 for he writes that ONLY for the Antec 330 and its 204W is more than most of the other PSes put out on that rail. It's crap like that that make the WHOLE thing suspect.

    .
  • by MosesJones ( 55544 ) on Monday August 11, 2003 @08:49AM (#6664622) Homepage

    DOH! NOW I know why my home build PC isn't working. I also made the "often made" mistake of forgetting the Power Supply.

    I'm glad to know this is a common mistake and not just me being stupid.
    • by Anonymous Coward
      So you have decent memory which has been thoroughly tested, a hard disk drive which matches it's controller, no hot spots [espcially around the cpu,3D graphics card and northbridge], well sorted BIOS, no interupt conflicts, a decent OS and compatible drivers for each device, then yeah, it's probably the power supply.
    • by wukie ( 684014 ) on Monday August 11, 2003 @10:55AM (#6665531)
      When I built my PC, the power supply was the first thing I considered.

      I was looking at building a Dual Athlon system on a Tyan motherboard with a few hard drives.

      Essentially to cut a long story short, this combination requires a VERY HIGH power rating on the 5 volt rail. Some 550W power supply don't cut it, Enermax units below 400W were uncertain, while Antec's 350W or better are fine.

      I went for an Antec 430W and their server case. 8 fans all attached to the "special" fan rail which adjusts their speed according to conditions keeps the computer humming.

      Corsair ECC memory, HD's with 3 year warranty help with stability aswell.

      Bottom line: Win2k - never had a BSOD (Blue Screen).Linux is obviously rock steady aswell.

      I would have considered an Asus or Gigabyte motherboard. Kingston, Micron or Infineon RAM. Chieftec or Thermaltake case. BUT the power supply had to a very good one ... i.e. ANTEC!
    • "DOH! NOW I know why my home build PC isn't working. I also made the "often made" mistake of forgetting the Power Supply."

      I actually have 'solved' problems on IRC help channels where the person said that their computer would not power up no matter what they did. The solution of course was to flip the power switch on the back of the PSU ;-)

  • by Anonymous Coward
    OK I'm no power supply geek, or electrician type either, but how much power is typically drawn from the wall in a pretty basic machine with a 400w power supply? A friend of mine is constantly being taken offline by his parents because they only let him use the computer for 2 hours a day due to power usage, and they're going on the wattage of the PSU in the machine he built. Personally. I think his machine (I think it's an 1800+ with one 7200RPM drive and a cd burner) would barely be using a third of that po
    • I'd of thought between and third and a half would be a reasonable guesstimate, but you've also got to remember they aren't 100% efficient, so you have to add on some wattage to acccount for that...

      There should be some device he could pick up at a local electornics store that could measure the amount of power the machine is using right?
      • by evilviper ( 135110 ) on Monday August 11, 2003 @11:07AM (#6665684) Journal
        There should be some device he could pick up at a local electornics store that could measure the amount of power the machine is using right?

        Search froogle for "Kill A Watt". I've got one and it works surprisingly well. Good luck finding it at any stores nearby. It's even a bit of a rarety online. (Check solar or radio shops)

        As I posted in a reply to his comment, my XP 2000+ is using up almost exactly 100watts, obviously that may vary a bit, but not much. Even an old 166MHz system of mine is using up about 60 watts. Interesting not though... Notebooks are FAR, FAR more power effecient. My 1.2GHz PIII Notebook with 10+" screen is only using up 19watts normally, and up to 32watts at moments with intensive processing or harddrive reads.
    • by Detritus ( 11846 ) on Monday August 11, 2003 @09:28AM (#6664849) Homepage
      Your friend's parents are mistaken. Just because the computer has a 400 Watt power supply doesn't mean that it is actually supplying that much power. It is probably considerably less. Think of it like the engine in a car. It may be capable of 150 horsepower but the average power output is much less.
    • Have your friends parents read this...then they can start taking his graphics card away after 2 hours instead.

      http://computer.howstuffworks.com/power-supply.h tm
    • by HidingMyName ( 669183 ) on Monday August 11, 2003 @09:44AM (#6664948)
      The best way to measure is probably experimentally. You could use a "Kill a Watt" device, that has a combination of a male and female plug with an output for indicating how much power is being drawn. You can get one for $40 U.S. or less.
      • THANK YOU!

        I have been looking for one of these things for ages. I keep thinking I'll have to make one eventually, because I couldn't find a commercial one.

        I searched for watt meters. I searched for power consumption devices. I searched for everything under the sun that might come up with these things, and came up blank every time. Now I plug in the brand name, and about fifty hits come up.

        Thanks. Going to see if anyone locally carries them, and get one ASAP.
        • Thanks. Going to see if anyone locally carries them, and get one ASAP.
          I've seen them at radio shack (but I couldn't see it in the on-line catalog. I seem to recall the price being around $30 or so, but the on-line prices appeared a bit higher for other vendors so I was conservative in my original post, because I didn't trust my memory on the price).
    • I remember my boss having power concern issues with our equipment at our co-lo facility. We had a bunch of low end RS\6000 kit that had 800W power supplies in them, thats almost 7 amps which is half the usage of most vaccum cleaners! It didn't seem right, these were older machines and not very powerful they couldn't possibly use that much power, so we grabbed a multi-meter to check the usage. On boot up (the most expected), the usage spiked up to just above 1amp (filling the capacitors I imagine) then dr
    • According to this [howstuffworks.com], a computer draws less than half the power of a refrigerator.

      I think their numbers are a little high, though. By their calculations, I should be paying $30/month just for the computer (which is on 24/7), yet I'm paying about $30/month for everything.
      • Their numbers are incredibly high... They are doing the same thing this guy's parents are doing, and assuming the rating on the power supply is the actual power drawn.

        Your computer is probably using up about 100watts, not 400, so divide all their stupid figures by 4 (and you should also use your own kilowatt/hour rates, not theirs).
    • That's silly. In my condo, the power bill shows exactly how much we spend on heating/cooling and how much we spend on everything else.

      In my 1-bedroom condo, my non-heating/cooling bill is about $17/month. That includes TWO computers running full time (one with a 400W supply: an Athlon XP 1900+; the other is a Pentium 133 used as an MP3 player), with a third computer that I frequently leave run on weekends. It also includes my stove, refrigerator, lights, television, DVR, fish tank with heater and filter
    • how much power is typically drawn from the wall in a pretty basic machine with a 400w power supply?

      I have no idea, it could be from 1-400watts depending on the system.

      A friend of mine is constantly being taken offline by his parents because they only let him use the computer for 2 hours a day due to power usage, and they're going on the wattage of the PSU in the machine he built.

      Your friend's parents are idiots. Even if it was drawing 400watts, that could be recouped by just shutting a handful of light

  • memory faults (Score:5, Interesting)

    by brejc8 ( 223089 ) * on Monday August 11, 2003 @08:54AM (#6664653) Homepage Journal
    The results of the memory tests [anandtech.com] are amasing. The MTBF is about an hour on some of the power supplys. I'm not sure If I understand the setup but that is appauling. I expect a MTBF of about 100+ years not an hour.
    • I agree completely. I run my machines for weeks with memtest86 [memtest86.com] before making them operational. And while I have found memory and motherboard problems, even with the most el-cheapo power supply it's either success or failure. This sort of reliably intermittent memory test failure that Anandtech regards as "normal" puzzles me to no end. Maybe it's just part of overclocker attitude?
      • Re:memory faults (Score:3, Informative)

        by dnoyeb ( 547705 )
        Weeks? really? Usually electronics fails in the first 24 hours, or its good to go. Especially where there are no moving parts.

        I dont think the added time is a proper measure of increased reliability.

        anyway, PSUs are overrated. I have used elchepos to the top quality units, and found differences in voltages, but not performance.

        I buy for sound now. But of course I dont run any high performance / demand servers either.
    • The results of the memory tests are amasing.

      Really??? 3 replicates of every test on a single sample. I haven't done the maths, but looking at the numbers I reckon some proper statistics on those memory test numbers would show up very little, if any at all, statistically significant difference.
      • Whats amasing is the fact that there errors are appearsing at all reather than one power supply being better than another.
        These errors sould not appear in a system no matter how poor your supply is
    • I don't think that a memory flip in the RAM means that the PSU failed.

      I dunno, the MTBF in RAM for any particular bit may be 100+ years, but once you apply such statistics on a system with multigigabite RAM, I wouldn't be too surprised to find a bit flip in a days's time.

      I would like more information on the test system, RAM brand, etc.
      • I did mean 100years+ for the whole memory.
        There is no way you would accept your computer crashing every hour. A bit change in the program memory will cause wrong behaviour and most of the time crash the application. If its in the data than it wont crash but it will corrupt a lot of important info.
        No way a computer would be useful with that sort of failure happening every hour. This would need heavy error correction.
    • The results of the memory tests are amasing. The MTBF is about an hour on some of the power supplys. I'm not sure If I understand the setup but that is appauling. I expect a MTBF of about 100+ years not an hour.

      MTBF means Mean Time Between Failure, NOT Mean Time Between Errors. What you are seeing is not a failure every hour or so, it's a certain number of memory errors during the specified test period. It's not amazing nor appalling that any of these supplies have the system generating an occaisional m
      • Yes but most computers do not have ECC nor parity on their memory.
        ECC might protect you and parity will simply allow you to crash out safely.
        Unless it was dont care memory this error would cause a failure of some form.
        I have run memory tests with quite dodgey memory, power supplies, fans etc. over periods of many hours and these errors do normaly not occur.
        Unless you went out to buy eec memory for your computer because you are scared these sort of error might occur over the lifetime of your machine then you
  • by Anonymous Coward
    I would like to see a review of all of the tiny power supplies out there. Espically all of the P4 compliant ones. I think alot of PCs will soon not look like PCs at all and they will still need power.
  • by Junior J. Junior III ( 192702 ) on Monday August 11, 2003 @08:59AM (#6664687) Homepage
    I really liked Anandtech's article. It actually had a lot of information and was fairly thorough -- measuring performance in a variety of ways, including not just output wattages but also noise levels, heat buildup, and cost.

    A bit more explaining the basics of what each different voltage rail is for and why x-level of performance is important would have been helpful. Along with some more basic stats, such as how long the power cables actually are -- surely people still build full-tower PCs, don't they?
  • External supplies (Score:2, Interesting)

    by Anonymous Coward
    All power supplies that I know of (not that much by the way) and all supplies tested are internal supplies. Since the powersupply is a major contributer to the internal heat of the box, and noise generation, wouldn't it make sence to make the power-supply external. It will decrease the temperature of the box, and by having it external you can place it at such a location where its noise is of least annoyance. You can even make them bigger, having larger (= less noisy) fans, and you could share them between b
    • Re:External supplies (Score:5, Informative)

      by ZorinLynx ( 31751 ) on Monday August 11, 2003 @09:32AM (#6664865) Homepage
      No, this would be a bad idea. The cables from the power supply to the system would be carrying low voltages, and to provide power to the system at those voltages would require high current. This would cause voltage drop (and thus loss) in the cables.

      When wiring up electrical systems, it is important to remember that your long runs should always be done with high voltage cable. For instance, from the wall to the power supply is 120V AC. Once the voltage is reduced, the runs need to be kept as short as possible, since every foot of cable loses substantially more power at the increased current required.

      50 watts at 120 volts is less than half an amp. 50 watts at 12V is about 4A. Big difference. }:)


      • When wiring up electrical systems, it is important to remember that your long runs should always be done with high voltage cable. For instance, from the wall to the power supply is 120V AC. Once the voltage is reduced, the runs need to be kept as short as possible, since every foot of cable loses substantially more power at the increased current required.


        Well, you have to also factor in that AC travels much better than DC. That debate goes back to Edison and Telsa, and Telsa got it right. That's why you
        • I hate to correct you, but AC does not "travel" better than DC. In fact, it's the other way around, though the difference is insignificant.

          AC is subject to the "skin effect", whereby more of the current flows toward the outside surface of the conductor. However, the skin effect is pretty insignificant at 60Hz.

          The reason why AC is used for mains power is because its voltage can be adjusted very efficiently using a very inexpensive and reliable device: The transformer. If you put DC into a transformer, you
          • Yeh, people always get that confused.

            I've had EEs tell me that normal high-voltage power lines are all DC. 0_o

            The interesting thing is that now that there are better methods for stepping up DC voltages to high levels, you're seeing more DC power lines.

            Generally, those lines are used to connect together various segments of the electrical grid that aren't properly wired together via normal high-voltage lines. Its a way to more easily transfer power to where it is needed and thus increase the overall effici
        • Minor correction: I think you meant Nikola Tesla, not Telsa.
    • wouldn't it make sence to make the power-supply external.

      Not if you must pass FCC (or CE in the rest of the world) radio frequency emissions tests.

      Those wires are going to radiate both the switching noise from the power supply and noise from the motherboard. They must remain inside the steel case to have any chance of ever getting the radiated EMI under the FCC class B limit, which is required for sale to consumers for use in homes. Even the higher class A limit (allows more noise, for business use wh

  • by Anonymous Coward on Monday August 11, 2003 @09:13AM (#6664760)
    Single-page link. [anandtech.com]
    • Thanks!

      It would seen that they are wasting their bandwidth just to get 28 ad exposures, with each "page" having only two paragraphs worth of comments and reloading their huge menu bars every time. Why do hardware sites have to be so ugly and absurd?
  • by WIAKywbfatw ( 307557 ) on Monday August 11, 2003 @09:15AM (#6664769) Journal
    ...but it strikes me that these reviews of PSUs aren't as accurate as they should be. I'm not wanting to run the guys at AnandTech or elsewhere down (because, most of the time, they do a great job) but it strikes me that, when you look at PSUs (as opposed to CPUs, graphics cards or HDDs) then perhaps testing just one sample of each product is flawed.

    After all, some of the measurements taken to distinguish good from bad were to the fifth significant figure. It strikes me that if you have to be that precise to differentiate between the winners and the also-rans then you've got to test more than one of each PSU - three would be a minimum, five or more would be better - and average out the test results to give you figures that are more representative of the quality of these products.

    After all, not every Zalman ZM400A-APF is going to have a 12V min/max fluctuation of only 0.005V, and not every Enermax EG651P-VE FMA 550W is going to have a fluctuaction of 0.65V. Who knows, perhaps this was just a particularly good Zalman and a particularly bad Enermax? Testing more units means accurate results, which is a good thing.

    I appreciate that testing three (or five, or however many) of each PSU means more work - you have to get x many more of each unit, test x many more times, process x much more data before averaging out your results - but, sometimes, I think it's warranted. Without wanting to get down on anyone, I'd like to suggest that, where called for, they try to source more units and test more thoroughly.

    And, before people start flaming me for not knowing what I'm talking about, how much work is involved, etc, let me just say that I've run a review lab and I do know what I'm talking about, how much work is involved, etc. It's not a trivial amount but, sometimes, it is worth it.

    (No doubt that's just a cue for half a dozen people to tell me where I'm wrong. I welcome objective criticisms but you can keep any childish flames.)

    • After all, not every Zalman ZM400A-APF is going to have a 12V min/max fluctuation of only 0.005V, and not every Enermax EG651P-VE FMA 550W is going to have a fluctuaction of 0.65V.


      If the fluctuations are due to the switching power supply and regulator design, then yes these measurements are going to be similar on other samples of these models (assuming no revision changes).

      Modern electronics components are amazing reliable and consistent as long you don't use surplus parts (or capacitors made from inco [ieee.org]
    • Why publish only an average from the 3 [or more] supplies.

      Publish each supplies results, averages and deviations.

      My computer (Dual Athlon on Tyan mobo) hammers the 5 V rail, so test on a few motherbords with quirks would help aswell.

      People usually get a 550W supply to power multiple hard disks, usually in a raid configuration. They should have done this aswell.

      Lastly, there is a variety in case designs. They should have tried a few cases and test for temperature and noise levels.
    • He didn't even test the power output of these PSU's, he just got the specifications off the sticker and compared them. The only real testing he did was the memtest86 results.

      Overall, a very poor article. The reviewer is known for poor, and unscientific reviews on anandtech. I don't know why they let him print his articles on that website. Usually Anandtech knows not to print crap that isn't sound.

      If you look up that reviewer's past articles (mostly on aluminum cases) he goes through the same crap. Testing
  • Where's the EE beef? (Score:5, Interesting)

    by AragornCG ( 246184 ) on Monday August 11, 2003 @09:15AM (#6664772)
    Great, there are more power supplies, but where are the oscilloscopes? Where is the detailed methodology for testing the cleanliness of the resultant power? They used some "stuff we found in our local university basement" to satisfy "you EE types". Oh, great. LIKE WHAT?

    I'll take a smaller review with decent scientific methodologies, thank you very much. There's more to stability of a power supply than "interference testing" which reports an integer number of errors that could be caused by anything... What about the thermal testing... where was it measured? by what, the onboard mainboard thermistor, which is notably unreliable? Which "industry standard Chenming case" was it?

    I really, really, really wish that these hardware sites would hire people with a decent understanding of the discipline of science - let alone engineering! - to write reviews. I could make MUCH more informed decisions.

    -Ben
    • We all know good power is important. But here i have seen the first test that shows that the power supply is related to flipping random bits in the memory.

      That is a mucht better test than tom [tomshardware.com] did: Just put a lot of load on a PSU and see if it dies. If it dies in flames then take a picture of it and put it on the front page. (Since it did not flame like the picture it is a fake)

      That is also better than the test of ars-technica: put a scope on the powerline and show the ripple. This looks horrible, but if
  • Altogether now... (Score:3, Insightful)

    by Zog The Undeniable ( 632031 ) on Monday August 11, 2003 @09:16AM (#6664781)
    Who, among home users, just buys the cheapest PSU they can find with enough power? Or is it just me? Some good reasons:
    • On my machine the CPU fan drowns out the noise of any PSU
    • With the way things are going, I'll need to buy a different PSU next time (ATX may die out, or everything will need 450W)
    • You can't see them, so they're not sexy
    • They make no difference to performance
    • Most of them last a reasonable time. I've been running different PCs for an aggregate of 11 years, and I've had one dead PSU in that time, costing 30UKP to swap out.

    You could argue that people running servers should care even less, because they normally have redundant PSUs.

    /me dons asbestos pants

    • Re:Altogether now... (Score:3, Interesting)

      by _|()|\| ( 159991 )
      On my machine the CPU fan drowns out the noise of any PSU

      The power supply fan has always been louder than the CPU fan in my computers. I had a generic 300 W PSU that I thought was too loud. I replaced it with a PC Power & Cooling "Silencer" that was just as loud. I later got an "ultra-quiet" QTechnology PSU from Quiet PC. Little, if any, improvement. Noise is important to some people, and it appears to be a difficult problem to solve.

      Not too long ago, 300 W PSUs were considered extravagant, but it's

    • Re:Altogether now... (Score:4, Interesting)

      by Zathrus ( 232140 ) on Monday August 11, 2003 @10:08AM (#6665106) Homepage
      On my machine the CPU fan drowns out the noise of any PSU

      I'm sorry... maybe you should look into quieter CPU fans in the future? Personally, the Zalman flower fans look very attractive to me... not in a visual sense, but an auditory one.

      They make no difference to performance

      They certainly do. Inadequate power supplies can cause system lockups and shorten lifespan of components due to improper voltage regulation... sure, that card can run with the 3.3V line at 3.6V, but you think that's not going to have some effects down the line?

      Put enough components in a system and you'll find out fast how much PSUs matter. Stick in 4 or 5 HDs and your system may not even power up -- even with a 400W PSU. Why? Because that "400W" PSU only has a 10A 12V line, which is utterly inadequate to spin up more than one drive along with a modern P4 or Athlon. Realistically it shouldn't even be used then, because you're well over 80% draw -- at which point voltage irregularities and noise concerns become a bigger problem. That system lockup? Yeah... it was caused by your CPU going wacky. Which was caused by the power supply introducing so much noise that the motherboard voltage regulators couldn't filter it out and fed the CPU bad power.

      You're talking about another $30 to get a decent PSU... it's not going to break the bank.
      • Personally, the Zalman flower fans look very attractive to me... not in a visual sense, but an auditory one.

        They look very attractive in an auditory sense? I think I see what you're saying....

    • Why would you want to hang $2000 worth off hardware off a $10 power supply? Particularly as when you overload that cheap power supply by accident (putting in too many hard drives, upgrading to a far more power-hungry CPU or whatever) it may burn out and trash your CPU, motherboard and RAM in the process.

      Personally if I'm spending that much money on components for my system I like to have a decent power supply to run them and the knowledge that if I do screw up and overload it it will just shut down nicely:
    • Who, among home users, just buys the cheapest PSU they can find with enough power? Or is it just me?

      That's a big ME TOO here. Although I usually go for the second-cheapest after checking the full specs.

      On my machine the CPU fan drowns out the noise of any PSU

      Same here currently, that's why I just invested in a Volcano 9. Extremely quiet at low speeds, and less noisy than my current CPU fan when it's at full speed, and twice the (CFM) airflow. Besides, it's the cheapest good CPU fan I could find.

      Also

    • In the past year in my household the following parts were fried due to inadequate power/protection

      2 motherboards
      1 CPU
      2 hard drives
      5(!) network cards
      2 CD-Rom drives

      these were out of three computers. One of these computers has a top of the line PS in it, as well as being hooked up to a UPS. That particular computer had 1 network card blow (some kinda surge hit our cable modem, took out the modem, router, and 2 network cards).

      These experiences have taught me that power supplies do indeed matter. S
    • > Who, among home users, just buys the cheapest PSU they can find with enough power? Or is it just me?

      Sorry to burst your bubble, but I *HOPE* it's just you.

      For the last YEAR I've been fighting all kinds of system instability, basically ever since I upgraded to a high-speed Athlon motherboard. I naturally thought it was mobo related. I was having crashes about every 10 minutes of heavy dual-drive activity (any time I was copying large files from CD-to-drive, or drive-to-drive, and it happened in both D
  • No dB ratings? (Score:4, Insightful)

    by Anonymous Coward on Monday August 11, 2003 @09:19AM (#6664794)
    I'd expect anyone reviewing power supplies to have provided some analysis of the noise generated by them. Since that isn't the case here, I'll stick with the original source material (read "manufacturer's promotional literature") instead of Anandtech's promotional review.

    Less clicking, at any rate.

    As a requisite disclaimer for the "It's Just Fine For Me" folks: While it may be true that certain electronic components are being engineered to be quieter, it's still the case that manufacturers rarely advertise/publish noise levels. The fact that there is a booming cottage industry devoted to quieter replacement components is evidence enough that manufacturers haven't yet fully addressed the needs of computer owners who are starting to discover that their nagging headaches and frequent innability to concentrate is due in large part to that box under their desks.

  • Who cares? More to the point, who cares about articles that decide reliability based on a sample size of one?

    Are we just killing time while we wait for the next SCO rant?

  • by plcurechax ( 247883 ) on Monday August 11, 2003 @09:32AM (#6664862) Homepage
    I just built a new Athlon XP (2600+) based system, and the power supply was the most frustrated part to get working correctly. I bought a generic case with a 300W Pro-Power ATX power supply. It had useless regulations, the 12V rail measured at 12.8V with the system on and idle, and jumpted to 13.2V when running some math calculations that I use for stress testing (www.mersenne.org).

    So I spent a Saturday trying to find a local computer dealer open that had any power supplies in stock. Most were sold out because of recent lightning storms (note: most didn't fail right away), anyhow about 2 hours of looking and driving I found a Codegen 300W ATX supply. It didn't setup off the SilentPC power alarms, but it failed the stress testing, with errors in about 1 hour of testing. The CPU temperature was fine (40-42 C) but I suspect the power wasn't clean which introduced memory or logic glitches.

    Finally after a week, I got a ThermalTake 360W power supply and my system works fine.

    So anyone who has an unstable system, it may not be all the fault of the OS, but poor or underpowered power supply.

    • the power supply was the most frustrated part to get working correctly

      Although it's possible that you were having a power supply problem, believe it or not, it sounds more like your mobo is poor, and very picky about power.

      I do buy very cheap power supplies, and after hundreds of them, not a single one has had a running problem (a few didn't power-on though).

      So anyone who has an unstable system, it may not be all the fault of the OS, but poor or underpowered power supply.

      It's not likely at all that the

  • by xyvimur ( 268026 ) <koo3ahzi AT hulboj DOT org> on Monday August 11, 2003 @09:37AM (#6664892) Homepage
    "Power supplies tend to be one of those forgotten, but ever so important parts of machine construction..."

    Here [google.pl] you can see why you should pay more attention when buying supply...
  • by gr8_phk ( 621180 )
    How about one with no fan. We build >600W 12V motor drives in small sealed boxes for under-hood (125C ambient) applications. We don't have a $&^%# fan. Why then must my PC be so loud at room temperature?
    • by battjt ( 9342 )
      I have an old 486 running as a router, that I ripped all the fans out of (cpu and power supply). It runs in the attic of a garage. No problem. I did open all the slots across the back. I'm probably getting some stack effect ventilation. Joe
  • by dpbsmith ( 263124 ) on Monday August 11, 2003 @09:49AM (#6664980) Homepage
    For as long as there have been micros, we have played the game of "by guess and by gosh."

    Why doesn't every card and component in a system have a clearly marked indication of its power requirement?

    And why don't power supplies issue unmistakable warnings when the system draws more power than the supply can reliably provide?

    Every fuse and circuit breaker in a house has the amperage clearly marked on it, and so does every appliance.

    Why can't the insides of our computers come up to the same standards as our toasters and washing machines? This isn't rocket science, this is simple arithmetic.

  • by Anonymous Coward
    For you do-it-yourselfers:

    Don't underestimate the importance of power supplies, nor assume because the box says "400W" that it really is, nor assume that any particular rail - +12V, +5V, +3.3V has the current you need. Sagging voltages on any rail can have mysterious effects that you will otherwise blame on your motherboard, the BIOS, memory, cards or the OS.

    I was the victim of an underpowered power supply when I upgraded my motherboard, and of course, I blamed the motherboard. Of course, my suspicions we
  • by Awptimus Prime ( 695459 ) on Monday August 11, 2003 @10:17AM (#6665196)
    I used to buy whatever 450 watt CompUsa model I could get for $19.00. That was a big mistake.

    After about 6 months use, I had one make a popping sound, then erupt in smoke. All I had in the box was dual 700 cpus, 6 scsi drives, 2 ide drives, cdrw, GF3, and a bunch of neon lights. During that time, the system would freeze up a lot, usually while compiling.

    Basically 450 watts doesn't mean as much as the quality of components and how cloesly the manufacturer was willing to run them to the point of breakage.

    I swapped out my burnt 450 watt for a Antec cool blue running at around 400 watts and my system is quieter and never locks up anymore.

    When reading wattages of cheap PSU's remind yourself of audio equipment. Like when a brand like Sparkomatic or Jensen promises 1000 watts out of an amp only for it to sound like shiat and blow speakers. Meanwhile, a Bose amp of 75 watts would be generating more power overall and not be tearing your speakers up. The same game is played with PSU promises. They, the generic cheapies, never planned on anyone using all 450 watts of their equipment. These big number, low performance parts are meant for a consumer with a very basic system seeking comfort big specs.

    I guess it reinforces 'You get what you pay for'.
  • I'm running a Duron 850 with 256MB of 133MHz SDRAM. GeForce2 GTS video card, SB Live, an ethernet card, and a generic 56k modem. Also, two HDDs, a CD-ROM drive, and a floppy drive.

    When my computer is off, the PSU switch in the back is also off. I turn on the PSU switch, and then press the case button. Drives spin up, fans come on, but no screen. No USB. No beeps.

    However, if I 'rock' the PSU switch, causing the system to 'brownout', the system will boot just fine, but I have to 'rock' the switch just
    • Re:My PSU (Score:3, Informative)

      by Durrik ( 80651 )
      Sounds like your power supply can't handle the inrush current for the start up of your hard drives and fans.

      When motors start up they have to get over the standing still friction of the unit before they get over the hump of startup and then into the lower friction of a moving unit. I would put in a nice graph but slashdot won't let me.

      What the graph looks like is there's a rise up to a peak. Doing an integration under the line to the peak gives you the force needed to get to the peak. This is the force
      • > I haven't built a system for close to 8 years and my knowledge
        > might be a bit dated

        A little over 6 for me, I know how you feel.

        As for his in-rush problem (I'm pretty sure that's exactly what it is, BTW), depending on his SCSI drives and controllers, he may be able to get the controller to spin them up one at a time after the controller's BIOS has initialized (and hence all the fans, etc are running).

        Back in the day, the Adaptec-1542 supported this if you hit Ctrl-A during boot-up and walked the
  • Wattage hype? (Score:2, Insightful)

    by zapp ( 201236 )
    It seems to me that there is a trend going about for high wattage PSUs. Don't most systems (even high end Athlon XP's) idle at something like 150w with a hard drive and cdrom, and video card in?

    Don't these systems peak at something like 200-250w (with 3d card suckin juice, and 100% cpu usage, etc).

    Why the hell would you pay $150 or so for a 450 or 500w (or more!) system? Unless you're running multiple CPUs or some sort of file server with a whole bunch of drives... I just don't see the point, it's just go
  • by lcsjk ( 143581 ) on Monday August 11, 2003 @11:03AM (#6665630)
    As one who has spent some 16 years designing power supplies for computers and other devices, I found the article to be very weak in factual information.
    Power supplies have an actual efficiency of about 75%, and no better than 90%, no matter what brand, Efficiency varies with loading.
    Quick spin-up on hard drives takes about 5 times as much 12V power as is required for running, but little 5V change.
    The actual voltage needed by components is not nearly so critical as the amount of noise (ripple and "switching" noise. (These are switching power supplies.) The nearest thing to a noise measurement test was the memory test.

    Output regulation is also dependent on the loading of the 5 volts or 3.3 volt outputs. Expect the 12 volts to follow the 5 volts as the processor and MB requires more or less computing power during operation. Some are independent, but most are not.

    Things like temperature testing can be very meaningless. Most components are designed for operation at an ambient of more than 70 degrees Celcius. The switching transistors will produce the most heat, but a small capacitor setting downstream in the airflow may be the first long term failure. Probably input to output is the best indication.

    Note also that the power supply fan sucks hot air from the PC and sends it over power supply components before exhausting to the outside air.

    The one test I found most interesting was the memory test, and although I am not sure of the methods used, the results do indicate overall performance. (Yes, I have also designed memorys and been involved it testing of memory chips with walking ones and zeros and checkerboard patterns etc. Without knowing which row of memory transistors is adjacent to the one being used, pattern testing is basically meaningless except for one word at a time.

    A few years ago I took a Sparkle (SPI) power supply and a Fortran power supply apart and the insides were identical - completely. Fortran was about $3 more in hundreds at the time. My guess is that they were made on the same production line. Are they the same or had one just been copied.

    The power supply continuous output rating should be the one used when talking about a 300 watt power supply, not the power line rating.

    Finally, audible noise. Bigger fans, lower speed, less noise. Fans mounted on the inside instead of near the back panel produce less noise.
    Fans blowing onto holes instead of through a circular guard produce more noise.
  • "Power supplies tend to be one of those forgotten, but ever so important parts of machine construction."

    That's why they make an appearance on /. every ten days or so.
  • Sometimes digging around on sites like Directron [directron.com] is a big help when you need to jam Econo but you want quality parts in your machine. I got a power supply made by Lite-On [liteonit.com] (same company as the Gold Standard of optical drives) for Compaq for use in their servers. It is conservatively rated at 300W but has been stress-tested at 380W and didn't even break a sweat. Here's the link [yahoo.com], sorry they don't have any more of them. $20 to purchase. I paid $10 extra to test the thing as good before they pushed it out the do
  • While you may never see any problems running PCs with cheap power supplies on a daily basis, they often suffer catostrophic failure after six months or more of use. I had one machine that ran flawlessly as my home server for over a year but one day when I was re-running power cables (exterior to the case) the power supply literally exploded when I powered the machien back up, destroying ever single component inside! Since I've started talking about this, I have found that something similar has happened to
  • I'm looking for a power supply in the minus three hundred watt range.
  • by Animats ( 122034 ) on Monday August 11, 2003 @12:33PM (#6666617) Homepage
    That article was very lightweight. They didn't do tests that any competent QA shop would do.

    Tests they didn't do, and should have:

    • Look up the UL certification [ul.com] for the unit, and check that the unit actually passed UL testing. Many power supplies, especially from China, have forged UL certifications. (UL had about 80 shipments seized at U.S. Customs last year for this.) UL's test include surviving a dead short and not catching fire for any single component failure. Uncertified power supplies are almost always the ones that catch fire.

      Checking the UL database is easy. Check any power supplies you have, and if the E-number isn't in the database or doesn't match the unit, report it to UL and have a serious talk with the seller.

    • Test the power supply with input voltages at the bottom and top of the rated range, and measure the regulated outputs. This is basic stuff.
    • Test the power supply in a hot box, with temperature maintained at the high end of the specified temperature range. This should be done with the unit loaded up to its rated load, and should continue for at least 72 hours. This, again, is a basic QA test.
    Those are all basic. The "memory test" was interesting. That's an indication that these power supplies differ in their ability to sink RF noise coming in on the power rails. That, too, needs to be tested.

    Nothing Anandtech did seemed to use a 'scope, let alone a spectrum analyzer.

  • by Futurepower(R) ( 558542 ) on Monday August 11, 2003 @02:10PM (#6667576) Homepage

    More and more companies are basing their business plans on taking advantage of the overclocker, gamer, case modder, or PC enthusiast who doesn't have much technical knowledge. These have slick sales literature and fancy graphics. They also may have no one at the company who knows or cares about the technical details of the product. I feel qualified to say this because, back when I was an electrical engineer, I have designed power supplies and industrial power control devices.

    "Monster cables" won't give you better audio than cheap wire of the same gauge. Similarly, paying a lot of money for a power supply is very unlikely to get you any difference in computer performance, provided you buy a quality low-cost supply.

    We pay $26 wholesale for our 350 Watt KingWin Kwi-350W power supplies, and they are fine. Froogle.google.com says they can be bought retail for $32 [google.com]. The AnandTech article discusses the Kingwin KWI-450, which they say costs $95. Why didn't they review the supply from Kingwin that is 1/3 the cost?

    One guess is that the entire AnandTech article is a hidden Directron.com advertisement. Maybe Directron.com does not want you to know that you don't need to pay more, and that you will derive no benefit from giving Directron more profit.

    The AnandTech article says, "Directron.com [directron.com] let us pick one of every new power supply off their shelves in order to put together a sample of 18 of the newer power supplies on the market right now."

    The article says about the Kingwin KWI-450WABK [anandtech.com], "We received our quad fan Kingwin supply well before the TTGI units had hit American soil. The unit was well received in the lab, but as we noticed when the TTGI units arrived, practically identical in construction. TTGI and Kingwin obtain their components from the same manufacturers in Taiwan."

    "Practically identical" does NOT mean identical. Directron's 350 Watt TTGI TT-350SS [yahoo.com] is $28.99. It looks a lot like the KingWin 350 Watt supply, but is different; the TTGI supply does not have most of the labels that are on the KingWin supply, for example.

    Look below at that link for what Directron says about their warranty: "Customer is responsible for returning defective products including DOA due to manufacturer unless testing is paid before shipping." DOA means "Dead on Arrival". Very clearly, Directron says that they do NOT stand behind their products.

    Directron's warranty may be translated as, "If what we ship you doesn't work, tough luck, don't bother mentioning it to Directron, you are on your own, complain to the manufacturer, and pay the shipping costs to where the manufacturer is located, but we won't tell you in advance where that is, because you might buy directly from the manufacturer." Only if you pay more will Directron stand behind what they ship. So the true cost is not $28.99, unless you want to take your chances.

    I suspect, and I have plenty of evidence, that when companies ask you to pay more for testing if you want a warranty from them, you get absolutely no testing. What you get is only the right to return a DOA unit to them.

    Notice something else about that Directron page. The price is an image [yimg.com], not text, from a different server, yimg.com. Does anyone know why they do that? I don't.

    There is plenty of evidence that the people at AnandTech have little technical understanding. Maybe the site makes money by doing things their advertisers want, which may be different from what is good for you.

    The first page of the AnandTech article [anandtech.com] says, "We then ran several exhaustive tests on these pow

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