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Hardware

Five Power Supplies Compared 263

Posted by CmdrTaco from the don't-take-it-for-granted dept.
EconolineCrush writes "Tech Report has done up a comparison of five high-end power supplies that looks at actual voltage levels and AC ripple content. The article also takes a look at environmental factors like noise levels and each power supply's impact on system temperatures. Think power supplies with like wattages are created equal? Think again."
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Five Power Supplies Compared More

Five Power Supplies Compared

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  • Is there something that these power supplies contribute towards overall system stability that "cheap" ones don't? Are they really worth the money?

    The article was very good at measuring everything measurable about the power supplies, but didn't answer the question "Why would I want one of these?". So why would I?
    • As an addon to that question...

      Is it worth buying two cheap-o power supplies that cost less combined than an expensive one so you have a spare?
      • Is it worth buying two cheap-o power supplies that cost less combined than an expensive one so you have a spare?

        Would you rather buy a pair of $40 PSU's, have one crash 12 months in, lose all your data due to faulty power to the hard drive, then install your backup (which will likely crash also, as it's in the same system)? Or would you rather spend $120 on a quality PSU, not lose your data, and probably never burn out?

        I think a bit of money is worth it because over two years, the extra $40 will hurt yo
        • Not trying to dispute your claims here, just relaying my personal experience. I have two PCs with no-name power supply units. One PSU has lasted over two years with no problems. The other PSU is only about 9 months old (entire system is only 9 months old) and is exceeding my expectations. I'm only 5W below the 350W ratings on both PSUs, too. I paid $50 for one and the other came with my $30 case. So, to answer the grandparent's question, I do think it would be worth buying two cheap PSUs.

      • Re:So what difference does a good power supply mak (Score:5, Interesting)

        by Lord Apathy ( 584315 ) on Tuesday August 05, 2003 @10:31AM (#6615397)

        Well lets see, I had one of those cheap no name powersupplies in my last system. One night it blew up. That in itself was pretty cool, had fire and shit shooting out the back of the case, smoke coming out all the holes. Now for the uncool part, every thing in the system was toasted. About 1500 bucks worth of system up in smoke.

        I guess it could happen with any powersupply but in this Beast I bought the one they recommended last year.

    • Re:So what difference does a good power supply mak (Score:5, Informative)

      by neodymium ( 411811 ) on Tuesday August 05, 2003 @09:32AM (#6614918) Homepage
      Good PSUs contribute a lot towards system stability. For example, a moving head in the HDD causes current transients (so does a CPU switching between normal operation and power saving mode). Bad PSUs have huge voltage drops during these transients, good PSUs can buffer them quite well. These transients can cause anything between nothing and total system crash.

      Also, the ability to filter noise out of the AC helps with stability...

      • Re:So what difference does a good power supply mak (Score:5, Interesting)

        by Smallpond ( 221300 ) on Tuesday August 05, 2003 @10:13AM (#6615209) Homepage Journal
        That's true. The hdd motor and head positioning is usually running on the 12V supply and its current profile is on/off at fairly high frequency.

        We used to estimate power supply quality by weight. The heavier, the better, since it meant they had more iron. Bigger transformers = better magnetic storage = better voltage stability. Now the switching frequencies are high enough that you don't need big iron cores. But you do need a switching frequency that is a lot higher than the load current frequency. Otherwise the 12V won't be stable. Not that they will tell you the switching frequency in a spec.

      • Re:So what difference does a good power supply mak (Score:5, Interesting)

        by jfw25 ( 618692 ) on Tuesday August 05, 2003 @10:23AM (#6615295)
        a moving head in the HDD causes current transients

        Indeed, I was disappointed that their testing regime didn't include any disk seek stress tests; a test which forced two disks (or more) to simultaneously seek from track 0 to track N would would exercise the PSUs' transient capacity really well.

        Many years ago, a development system I was using had a cabinet with four disks in it. Every once in a while, during parallel makes, all four disks would spin down simultaneously. Eventually, we discovered that if all four drives were told to seek simultaneously (easy to do on a SCSI bus), the resultant load on the 12V line would pull it out of spec, the power supply would shut down, and the disks would spin down (releasing the overload and allowing the power supply to come back up, hiding the evidence). Since this box was a kludge, we "solved" it with a big, fat capacitor on the 12V line (next to the drives) to handle transients. (Which probably reduced the power supply's lifetime due to power up transients, but who powers down development systems?)

        Modern disks do draw less transient current during seeks, so this isn't quite the issue it used to be, but it is still a source of stress they ought to have checked.

    • Read this [anandtech.com] page from AnandTech's PSU roundup. The only thing that was changed between tests was PSUs, yet over a 6 hour time there was a range of only 1 up to 7 memory errors. Just one possible indication of how clean the supply is. Also there's the added benefit that it probably won't die in a month or two (happened to me, not too pleased when it did)
      • Also there's the added benefit that it probably won't die in a month or two (happened to me, not too pleased when it did)

        I consider you lucky. The PSU I originally put in my computer was apparently really horrible. Every time I turned on my computer, the system would crash within a few minutes and I'd have to restart, after which it would be fine until I turned it off next. This went poorly diagnosed for over a year. Eventually it started getting so bad that you could occasionally, and then frequently, hea

      • yet over a 6 hour time there was a range of only 1 up to 7 memory errors.

        Gees, I run my systems for years without a single memory error (mix of parity and ECC systems under my control). What the fuck was AnandTech doing wrong?

    • Re:So what difference does a good power supply mak (Score:5, Informative)

      by saskwach ( 589702 ) on Tuesday August 05, 2003 @09:38AM (#6614963) Homepage Journal
      In a cheap power supply, you can get inconsistent voltages, crazy transients, crosstalk, and if the power demand from one line goes up it can drop the wattage/voltage on the other lines. Cheap power supplies are also frequently noisier (sound too) than high end ones and run less efficiently (read: hot) than better designed, more expensive power supplies. Think about it: your computer operates because of well controlled voltages. If your voltage drops by 2V, some transistors will go into their linear range and cause crazy crazy crap to happen.

    • Re:So what difference does a good power supply mak (Score:5, Informative)

      by LookSharp ( 3864 ) on Tuesday August 05, 2003 @09:41AM (#6614990)
      See my reply here. [slashdot.org]

      The reason they check the voltages so closely is that one you start falling out of the 5 or maybe 10% tolerance zone for many components, over-voltage will cause overheating, lockups and early failure, and undervoltage also frequently causes lockups and occaisionally failure.

      Also, some supplies give you a total wattage without breaking down where those watts can go. When you're dealing with processors that pull 80 watts at peak, you REALLY don't want a cheap supply that is busy sending all available watts to 5 and 12 volt channels to power drives.

    • Re:So what difference does a good power supply mak (Score:5, Informative)

      by Tmack ( 593755 ) on Tuesday August 05, 2003 @09:42AM (#6614999) Homepage Journal
      Having worked at a computer repair shop, I can assure you, YES there is a BIG difference between cheap PS's and quality ones. Cheap ones will last only a few months on any newer system, they might last a few years on older ones. Blown PS's was one of the most frequent repair jobs, and anytime someone requested the cheapest part to replace it with, I knew I would see them in a few weeks. They also affect System stability, if the PS cant put out the power the computer needs, it will crash (and the PS will burn itself up sooner as well). Got frequent blue-screens/sig11's and cant find anything wrong? Change your PS to a better one, there's a good chance thats the cause. Go to a local computer shop and pick up a cheap one in one hand and a good one in another, you will feel the difference. I always recommend Sparkle (there are some re-branded ones made by sparkle, will have SP in the model #) and HEC, and although I havent RTF yet, I would bet one of those is at the top, and the other is close to it.

      Another thing to consider when buying a case.. the PS they put in cases are the CHEAP kind, unless they specify what kind it is, I generally expect to replace it within a year. A few years ago I had one of the dual socket370 BP-6 boards, it refused to boot on the PS I had that came with my case (Enlight none the less). I swapped it to a sparkle 300watt and have had no probs since.

      This was also recently covered by Tom's Hardware [tomshardware.com], and earlier by a few other sites. The sparkle and HEC normally blow away the rest, with their 250w beating the specs for most 300+w, and even being able to hold 300w operation themselves.
      just my $.02

      Tm

    • Re:So what difference does a good power supply mak (Score:5, Informative)

      by Jucius Maximus ( 229128 ) on Tuesday August 05, 2003 @09:43AM (#6615001) Journal
      "Is there something that these power supplies contribute towards overall system stability that "cheap" ones don't? Are they really worth the money?"

      If you've got weak voltages on the PSU rails, it can kill your HDDs. Some people lose drive after drive and never consider that their voltages are out of spec. Also, if your cheap PSU shorts on the DC side, say goodbye to your drives and maybe your motherboard and everything plugged into it.

    • Re:So what difference does a good power supply mak (Score:5, Interesting)

      by The_Laughing_God ( 253693 ) on Tuesday August 05, 2003 @09:48AM (#6615038)
      You've got to be trolling. On the off chance that you aren't:

      The article started right off by saying that system stability can be affect, that the stability of voltage levels and the amount of electrical noise varies greatly. It also noted that the power supplies distribute their power differently among the various output voltages The /. intro noted case noise and heat output into the case.

      The effects on the CPU, chipset and RAM of electrical noise and/or 'brownouts' of voltage dropping below specs should be obvious. I've seen several systems go instable because the 5vsb line, or some voltage branch like the USB line couldn't drive the attached components. What good is having 200 extra watts you don't need at one voltage, if the PS goes flaky at full output and real usage on another? A lot of power supplies that do fine (or almost fine) on a bench or at 50% of their rated current draw in the real world will flake out occassionally at 85%. A few milliseconds of flaking out ever several hours can turn a dream machine into a nightmare.

      Hook an oscilloscope to distal power traces on the motherboard (not near the power supply, and depending on your supply, you can see some pretty ugly stuff as peripherals/cards switch on/off. Sure, a good motherboard should have plenty of well placed filter caps, but on a fully loaded system, you can *see* how adequate they sometimes aren't, if the power supply doesn't supply great power in he first place. It's possible to design very rugged and tolerant motherboards (e.g. military), but in the consumer market, price competition is so tight that boards are often revised in mid-production to save one or two caps.

      I'm not saying top-of-the line is always best, but bottom of the line is pretty much asking for trouble down the line. Most people 'add and test' when they build (or expand a system with use), but the culprit may not be the card you just added; it could be the power supply you 'vetted' up front.

    • The most important information for you would probably be the ripple current test and the rail wattage information. Ripple voltage is the minute amount of under or overvoltage that your DC components are getting out of the power supply. Ripple is probably one of the most damaging side effects of an AC-DC conversion on DC components. In other words, get the power supply with little to no noticable ripple on the test. Everything connected to it will last longer.

      Rail wattage is also important because power su

    • I paid the price for using a cheap PSU.

      The damned thing blew up (went bang, magic smoke came out). When I fitted a new PSU, I found that when it went, it had taken out the motherboard, graphics card, both hard drives and CD-RW drive. The only survivors were the network card, DVD-ROM, keyboard and mouse. The fuse in the PSU didn't even blow.

      Meanwhile, the adjacent Sun Ultra 5, Dell PC, printer and other kit carried on running as it always has - so I doubt it was a surge in the mains power.

    • Re:So what difference does a good power supply mak (Score:5, Interesting)

      by swillden ( 191260 ) * <shawn-ds@willden.org> on Tuesday August 05, 2003 @10:21AM (#6615268) Journal

      I don't know if you'd want one of these top-of-the-line power supplies, but you definitely want a decent one.

      About three years ago I bought a case without checking the power supply in it and after about a month of operation my mainboard died. I blamed the mobo (it was also a cheap brand), and replaced it with a really nice one. That one lasted about a year, but was really flaky the whole time, especially the onboard Promise ATA100 IDE controller which had so many errors that I stopped using it. When I decided to buy a new machine, I bought better stuff but I (foolishly) replaced the mobo in that system yet again and gave the thing to my wife. Where I'd seen minor instability and annoying failures under Linux, she saw daily bluescreens with Win2K. Finally I bought her a new power supply and all of the problems went away (well, she's still running Windows, but I'm working on that ;-) ).

      So, at the end of it all, I'd say the $20 I saved on that cheap power supply cost me two motherboards.


    • Is there something that these power supplies contribute towards overall system stability that "cheap" ones don't?

      The short answer is they give you added margin against worst case power flucuation, load changes and temperature extremes. An old engineer I once worked with used to refer to such margin as "belt and suspenders". He'd explain that nobody ever lost their britches wearing both a belt and suspenders.

      The Zalman has superior voltage regulation and ran cooler. If you have a system that is very imp

  • Power supplies (Score:5, Interesting)

    by stratjakt ( 596332 ) on Tuesday August 05, 2003 @09:27AM (#6614882) Journal
    I seriously tire of "tech" reviews on stuff like power supplies, roll out keyboard drawers, cd holders, etc... This is the third "tech" article about power supplies I've seen here in a year.

    Here's all you need to know:

    Pick up two of the same rating, different brands. The heavier one is better - more windings on the coils and better components.

    The end.

    • wrong (Score:2, Interesting)

      by WARM3CH ( 662028 )
      Power supply unit (PSU) in modern PC is much more complex than what you think. Also, switching PSUs can be designed in so many different ways with so many different parameters in mind that simply refering to the weigth of the iron in the coil is meaningless. About the compoenents, I don't think that better componenets should necessarily weight more (why should a better MOSFET weight more than the other one??) Generally speaking, as the CPUs are more power hungry today, Graphic cards consume so much power th
    • I agree with you about most of the "reviews" here on /., but you have to admit that a power supply review is a hell of a lot more useful than most of the crap posted here.

      -prator

    • Re:Power supplies (Score:5, Informative)

      by swordgeek ( 112599 ) on Tuesday August 05, 2003 @10:52AM (#6615648) Journal
      People said that about speakers too. Heavier construction meant less vibration-induced distortion.

      So one company poured concrete in the base of their speakers. Even after the reason for their weight became clear, people actually still believed that they were the best speakers for that very fact alone.

  • older tests : (Score:5, Informative)

    by Anonymous Coward on Tuesday August 05, 2003 @09:27AM (#6614883)
    http://www.tomshardware.com/howto/20021021/index.h tml

    21 power supply tested here :)
  • in my experience quiet power supplies are quiet because they have slower fans, and so result in a hotter case. So you end up putting in faster & noisier case fans, and get back where you started.
    • Well, at least that TruControl one lets you move along the quiet to cool continum in software, without extra parts.
    • Er, not necessarily. Since heat rises, and the power supply is at the top, it shouldn't heat the case much anyway. Having recently switched from a loud PSU to a Zalmon power supply and lowered the voltage on my case fan from 12v to 7v (to make it less noisy), I've noticed only a minimal increase in temperature (still waybelow any max limits) and a blessed release from buzzing noises... I can now sleep with my PC at the end of the bed switched on, and more importantly, so can my girlfriend (admittedly not th
    • But hey, if you add "cool" cathodes and windows to your case, it'll be mad cooler. Windows totally let IR out of your case, cooling it. They also work silently. Another thing that works silently is filling your case with water and putting fish in it. It looks better and won't get over 20 degrees (and if you ever get a hankering for fried fish, all you have to do is turn it on).

  • Antec (Score:5, Interesting)

    by dlur ( 518696 ) <dlur&iw,net> on Tuesday August 05, 2003 @09:31AM (#6614906) Homepage Journal

    Before I read the article my guess was that Antec would win...and I was right. From the low end to the high end these guys have got their stuff together.

    Most of the cases we buy come with Enlight power supplies (they are Enlight cases after all for the most part). Although these Enlight PSes seem to be ok, I always replace them with a nice quiet reliable Antec when they are going home to me or to my family. I also recommend putting an Antec PS in to customers who buy the biggest, baddest gaming PCs.

    The simple fact of the matter is though, that most folks don't really need a 550 watt PS. A 350 watt PS will more than handle the load of most average consumer PCs. I do dread opening up an e-Machine or various other "value" (aka cheap ass P.O.S) PC and seeing a 130 watt PS running a P4 CPU. *shudder*

    • Antec makes excellent cases as well. If you're building a computer and don't wanna drop bank on a power supply consider an antec case + power supply combo.

  • Reliability (Score:5, Interesting)

    by GeckoFood ( 585211 ) <geckofood@@@gmail...com> on Tuesday August 05, 2003 @09:31AM (#6614913) Journal
    While all of these look good and they all have some pretty spiffy specs, it would have been nice to have seen some reliability test scores in there. A flaky power supply is a hard thing to track sometimes, and knowing which ones have the best chance of running reliably for the longest time period would be handy information, especially for those of us who have fought with bad power supplies at one point or another in the past.

    • Re:Reliability (Score:3, Interesting)

      by morcheeba ( 260908 )
      A good measure of reliability would be to find the temperature of the hottest component. Usually you can guess it'll be the transistors with the heatsinks, so you can stick a few thermocouples in there, close it back up (must keep airflow as the manufacturer intended), and run it for a while.

      Besides the environment*, heat is the other biggest killer.

      (* I was doing the mil-hdblk-217 [t-cubed.com] reliability measurements, where the environment ranged from lab to carrier-based-fighter-jet-externally-mounted. I think vibr

  • Ahh.... the beauty of power supplies (Score:5, Funny)

    by archeopterix ( 594938 ) on Tuesday August 05, 2003 @09:33AM (#6614923) Journal
    The funniest quote from the article:

    "Aesthetically, there's not much to see with the SilentX; it looks like, well, a power supply."

  • Durability, mtbf (Score:4, Interesting)

    by CausticWindow ( 632215 ) on Tuesday August 05, 2003 @09:34AM (#6614933)

    I've had so many powersupplies dying on me that it's not even funny. What I want is a PSU that delivers the promised effect, for at least three years. That would be the day.

    Might be hard to benchmark that, so anybody got any tips for brands?

  • AnandTech also just had a PSU roundup here [anandtech.com]. The watt numbers and some of that aren't the best from AnandTech's review (read some criticism of it here [anandtech.com]), but overal it's a good roundup, especially comparing heat and noise.
  • I own the Fortron and have had no problems with it AND the price was right ;)

    Power Supply Roundup Part 2 [anandtech.com]

  • Antec never disappoints (Score:4, Informative)

    by LookSharp ( 3864 ) on Tuesday August 05, 2003 @09:36AM (#6614944)
    As the article concludes, Antec is the best option available. I run a server with a 300 watt Antec powering the system, and a separate Antec 400 watt running ten of the eleven hard drives. The voltages stay tight and the supplies stay cool. The 500+ watt models are expensive, but the $69 I paid for the 400 watt is well worth it when you are protecting 1.1TB worth of drives.

    On the cheap/lower power side, I've had great success with Sparkle and Enlight (250-350 watt) supplies. Priced in the $22-$40 range, these are great for "normal" systems.

    I definitely recommend you stay away from the cheap stuff that comes in $30 cases, though... you'll see why when the supply dies, or shorts taking the mobo with it. :(

  • From the article. (Score:5, Funny)

    by Prince_Ali ( 614163 ) on Tuesday August 05, 2003 @09:37AM (#6614955) Journal
    Would you dare put cheap gas in a Porsche? Of course not, yet I continue to see enthusiasts putting cheap power into their high-end PCs.

    Where can I find this cheap gas now?

    • Re:From the article. (Score:2, Offtopic)

      by pogle ( 71293 )
      I hear it'll show up if you eat a lot of beans...
    • Beats me. Gas is gas, unless you've got some place that lets water run into their tanks.

      Maybe by "cheap gas" he means low octane? Indeed some cars require higher octane fuel. If you have a car that says 93 octane then certainly you don't want to feed it 89, but if it says 89, there's no point in giving it 93.

      Most standard passenger cars these days have NO reason to eat anything > 87 octane. Both of my cars, a 97 taurus and a 2000 Windstar, actually say in their owner's manuals that 87 octane fuel i
      • Gas is gas

        Not totally true. It's mandated in some areas to add "Oxygenizers" to the gas -- essentially alcohol. These reduce the number of available Joules in the fuel in a trade off for lower emissions. The gasoline mixtures also changes from summer to winter (making it less volatile in the summer).

        Some cars require higher octane fuel (as a Porsche would) because they run higher compression ratios and earlier ignition timing (resulting in higher cylinder pressures). This requires a fuel with a

  • AC Ripple Measurements (Score:3, Informative)

    by CMiYC ( 6473 ) on Tuesday August 05, 2003 @09:39AM (#6614971) Homepage
    For the AC ripple measurements it would have been better to put the scope in infinite persistance. Measuring the output over time doesn't really matter. Digital scopes spend the majority of their time sitting around, not measuring signals. So we are missing tons and tons acquistions between each acq.

    If he put the scope in infinite persistance we would have seen the ripple voltages grow over time. It would have provided a chance to see an overall (or even average) difference between idle and load.
  • It is strange that there are hardly any truly silent powersupplies, when there is almost no laptop with a powersupply that makes noise..

    If powersupply manufacturers simply take out the heat generating part so that you can have it well ventilated and only let the dc wires go into the case, then the completely silent pc would be so much closer.

    CC
    • Maybe because Laptops run off DC power, thus not needing the giant cooling fans to cool off the transistors/transformers/othercomponents since they are not needed? They are also designed around not needing much power, since they have to run off a battery. Desktops are also much more powerfull in terms of computing speed. At any given time, you point out the fastest laptop available, and there will be several PC's that can blow it away.

      Tm

      • And they do this by getting rid of the heat generating transformer. They put that in a wall wart or a cord wart (little box the dc cord comes out of and the ac cord plugs into). Thus no fan needed. Yes laptops run on DC, but those cords that run and chargfe it all when it's dead are run off of ac.

        • Most power supplies on both laptops and desktops are switching power supplies. Usually they just take the incoming 110V and convert it to high voltage DC; they then convert that to lower voltage by switching the high voltage on and off. They then use a big cap to try and lower the ripple that this would obviously cause. IF they do use transformers, they usually take the high voltage DC and oscilate it at a lot higher frequency than the 60hz that you get from the plug. If your AC power is oscilating at a hig

  • In other news.. (Score:3, Funny)

    by reidbold ( 55120 ) on Tuesday August 05, 2003 @09:48AM (#6615037)
    you get what you pay for.

  • PC Power and Cooling (Score:5, Informative)

    by EchoMirage ( 29419 ) on Tuesday August 05, 2003 @09:52AM (#6615056)
    Why is it that every time these "high-end" power supplies get compared, the most high-end one always gets ignored? PC Power and Cooling [pcpowercooling.com] has long manufactured the world's best power supplies. They're the Ferrari or the Moto Guzzi of the power supply world. Yeah, lots of Asian manufacturing firms make OK power supplies, but PCP&C's stuff is the only company that makes boards that the major motherboard manufacturers highly recommend and use exclusively in their own tests. Why does such an obvious high-quality product always get ignored?
    • Why does such an obvious high-quality product always get ignored?

      Because they dont give out free products for "review". They dont need to, as they dont sell to hobbyists through CompUSA.

      Articles like this are a form of marketing. The only "conclusion" they ever reach is "spend as much as possible!"

    • Re:PC Power and Cooling (Score:5, Insightful)

      by smithmc ( 451373 ) on Tuesday August 05, 2003 @11:14AM (#6615859) Journal

      Why does such an obvious high-quality product always get ignored?

      IMO, one reason is that they've missed the boat on a new trend in PC homebuilding - low noise. The top PCP&C PSUs are great from an electrical standpoint, but they're noisy. Meanwhile Antec, for example, has focused on PSUs that are high in quality and low-noise as well.

    • They aren't the only one that gets left out. There are a number of firms, mostly European, these days that are making power supplies designed to but noise. Some take power supplies from someone like Sparkle and redo them with better fans and some components, some make their own. While not for everyone, there certianly is a market for these things. Yet they seem to be universally ignored in reviews. This review is actually the first one I've seen that has one in it.

      Also other important features of the power
  • After several failing power supplies, earlier this year I decided to get a good power supply. I read their review (and assorted other reviews) last year and bought the TruePower 550.

    It is pretty quiet and has run great and it is nice to see it running so well against the newer models.

    I won't buy another cheap power supply again.

  • hmm (Score:4, Insightful)

    by Mike1024 ( 184871 ) on Tuesday August 05, 2003 @09:58AM (#6615104)
    From the article:

    Would you dare put cheap gas in a Porsche?

    Am I the only one who answered "Absolutely; gas is gas"?

    • Re:hmm (Score:4, Interesting)

      by stratjakt ( 596332 ) on Tuesday August 05, 2003 @10:07AM (#6615163) Journal
      Yeah, every 10 fillups or so I put the high-octane in, that's more than enough to burn off any residue in the engine. You get the exact same advantage as if you'd used it every time.
    • Yes you were. Because it isn't. Usually faster cars require better gas. Also, cheap gas is sometimes cheap for a reason...it isn't always the octane they say it is.
      • In addition, putting cheap gas into a high compression engine is asking for trouble. Ever have an older car "ping" under load? That's bad.

        Higher octane gas reduces the chance that there is unburnt "gas" in the chambers on the next compression cycle. If the unspent gases or carbon is still pretty warm, it'll explode early, and can damage valves, pistons, etc....

        (At least, that's my understanding of it...)
        • Actually, your wrong...

          High octane gas has a higher ignition temperature. It's used in performance engines because they, for efficiency reasons, are designed to generate higher cylinder pressures. Higher cylinder pressures means higher temperatures (basic thermodynamics).

          Having said that, high octane fuel actually contains fewer available BTU's than regular -- it's a trade off

          Older cars ping because carbon deposits form on the valves. These deposits hold heat and become hot spots which can pre-deto

    • Obviously you don't own a Porsche; or, if you do, you'll be replacing the engine soon... High performance engines almost always require high octance because of their higher cylinder pressures.

  • Four missing Parameters (Score:5, Informative)

    by mykepredko ( 40154 ) on Tuesday August 05, 2003 @10:07AM (#6615161) Homepage
    I'm not a power supply designer, but I do have some experience with system power supplies and their affect on system operation/reliability. If I were deciding upon a power supply for my system (or product), I would carry out the same testing as in the article, but also measure the following four parameters:

    1. Initial Power Up overshoot/ringing/stabilization. I would hope the supllies powered up with a basic RC curve "POWERGOOD" becoming active when each of the supplies are within 1% of their targets.

    2. Transient response. This is different from the "Load" test, it would look at how the power supply worked when it went from minimum load to maximum load and back again. Say starting up the disk drives, CD-ROM and change the fan speed at the same time.

    3. Transient response across supplies. What happens if there is a large transient on another supply. The different power outputs in modern power supplies are not as separate as you might think.

    4. Power down characteristics. Again, this should be a smooth RC curve with no overshoots or ringing. The high power positive voltage outputs should never go negative.

    The first and last parameters will be an indicator of how "gentle" the power supply is on the components and whether or not there is any danger of having them overstressed. The middle two parameters would indicate how reliable operation of the PC would be and whether or not you would get power supply induced lock ups or glitches.

    Power supply design is more art and component management than strong engineering application. Modern PC power supplies really are a result of iterative cost reduction and learned experience. A lot of "common sense" ideas are just plain wrong when applied to high current output switching AC/DC converters: I have learned that heavier is not always better and is often an indicator of an inefficient design. Fires are not uncommon in PC power supply testing and development and choosing the best power supply design is often a case of figuring out which company could best understand what the ashes were teling them.

    myke
    • #4 there is a big one. I've seen power supply voltages spike up after being shutdown. I never really paid attention to it until I was using a cheapo power supply on the bench to test some old 12V fans just to see if they'd spin. I noticed when I shut off the power supply, the fans would spin faster for about 1 second then start to slow down. Voltages were cearhing 14-15V on the 12V line at that time.

  • PC Power and Cooling (Score:4, Interesting)

    by neonfrog ( 442362 ) on Tuesday August 05, 2003 @10:12AM (#6615198)
    How come these guys [pcpowerandcooling.com] never make into the power supply round-ups? I have purchased several (as well as some Antecs, Acers, and more no-names then I care to remember, so no fan-boy fanaticism here) and they have been very reliable. I have a 10 year old AT style that is still working perfectly while several no names have died on me. Never lost one of these (purchased 5 or so over the last 10 years) as a matter of fact.

    I'm an MIS guy for a small company (10 people, 20 PCs -- go figure...) and I always look at PC power and cooling supplies as well as other brands when I'm building machines. I think they make great server supplies or swap in replacements for older machines at the very least.

    I have also used those guys for obscure CPU cooling fan options (try to find a quality replacement CPU fan for a Pentium Pro 200)! They stopped stocking them, but offered to make one up for a very reasonable cost -- I went with a different solution, but they were quite helpful. I have purchased several CPU fans from them and none have yet died.

    I usually go with Antec power supllies for new workstations because, in addition to running well, they come standard in good Antec cases that I'd want for a workstation anyway.

  • Nyquist would giggle at the ripple charts. (Score:3, Informative)

    by adamdeprince ( 600460 ) on Tuesday August 05, 2003 @10:12AM (#6615199)
    A/C ripple would be 60Hz (or perhaps some harmonic.) A 10ms sample is _woefully_ too short to see it.

    Also, of more interest in a switching power supply than A/C ripple would have been the ripple from the power supplies own oscillator ... it is my understanding that switching powersupplies shift the frequency to something substantially higher (1-10k Hz region.)

    Take a long (say 1 second) sample at a decent resolution (at least 120Hz for a A/C ripple, perhaps 100khz if you care for switching ripple) perform an fft, and look for the spikes at 60Hz and whatever the powersupply switches at.

    What they were showing was meaningless noise ... approximate amplitude was the only conclusion you could draw, but to say "look, A/C" ripple noise is just plain silly ... especially as the A/C ripple would be so much larger than the 10ms sample duration.
    • I believe the charts are mislabeled. They say nanoseconds at the bottom, but the clear 60 hz signal on the cheap ION one would be correct if the units were microseconds.

  • Let's get to the point.. (Score:5, Funny)

    by MongooseCN ( 139203 ) on Tuesday August 05, 2003 @10:16AM (#6615229) Homepage
    Which one will give me the best framerate in Quake?

  • Line regulation is important, too (Score:4, Interesting)

    by Ignis Flatus ( 689403 ) on Tuesday August 05, 2003 @10:21AM (#6615278)
    I just scanned the article, but I saw no mention of testing for line regulation. Maybe I'm just old school, but that used to be an important factor. Oh yeah, just thought of another one. Home users might be interested in knowing just how much noise that power supply is injecting back into your mains voltage. Switching power supplies are noisy little beasts.
  • Uninterruptible power supply, not United Parcel Service. Can you get away with having a cheap power supply if you have a UPS?

    I learned the importance of having a solid power supply when I moved to the unstable New Orleans power grid (damned third world around here). I fried 2 cheap ps's. My roommate went through 2 motherboards, and we've gone through 3 routers and 5 network cards. All of this in a year time frame. I finally got wise and bought antek for like $80 and a UPS for maybe $150 and I've been
    • Actually, I think it is funny that PSUs with integrated UPSes haven't become more popular. Just give me a minute of power, and I'll change that fuse, that's all I ask for...

      Probably, it is because very popular OSes crash so often that a little power blackout doesn't make much of a difference...

      I think it would be a good idea, though. And it could communicate with the OS through SMBus or something.

    • Offtopic, but I wouldn't worry about shielding the CAT-5. Just make sure you don't run your cat-5 runs near any of your mains power, or your power cords etc (follow the same practice you'd do with a home theatre -- keep power seperate from audio) and you should be fine.

      The only real gotcha there would be if your switch/router/whatever decided on a surge to throw a few extra volts down the line... at that point, if you've got the endpoints on UPS's, it shouldn't be an issue, but even electronics can break
    • Sounds like you need a UPS with continuous line regulation.

      In answer to your question, No. Having a UPS keeps the power supplies' supply (input) current stable; but, does nothing to prevent a bad power supply from producing bad, noisy power to the PC inards...

      If you're getting spikes on your network cables due to electrical supply spikes, which are destroying your network cards, It's not a shielding issue. Put the router / switch you are using on a UPS as well. The surges are most likely getting in thr

  • Thank you, comment posters (Score:3, Insightful)

    by indros13 ( 531405 ) * on Tuesday August 05, 2003 @10:38AM (#6615491) Homepage Journal
    I was a little disappointed in the article. Although they provided some nice data on power supplies, they left it to Slashdot posters to explain why I would care about a quality power supply (other than general "stability problems"). For example, how does A/C ripple affect system performance and stability?

    Another item I found lacking is that they only tested one power supply of each type. If you happen to get a bum PS from one manufacturer, you can draw faulty conclusions from the benchmark. They should have at least done two of each to see if there were wild differences. The Ion PS, which performed poorly in the A/C ripple (whatever that means), could have been a bad Ion PS. We'll never know...

  • Someday, my powersupply will burn down my house.

    In order to turn my computer on, I must first flip the power-supply switch (I always keep it off just for safety or something). Then I push the front power button. Computer comes on. Drives boot, fans come on, etc, but no screen. No POST, no beeps. I then have to 'rock' the power switch in the back where the computer browns out and only then if I do it correctly will the machine boot. Been doing this for a year and a half now, everything's ok.

    Might be
    • I found that with certain BIOSes on my ABIT BP6, if I had disks plugged into different onboard IDE controllers (UDMA66 or the standard), I'd have to do the same thing. I reflashed the BIOS (again) and the problem went away. Go figure. It's a weird one.

  • Case temperatures (Score:3, Interesting)

    by cr@ckwhore ( 165454 ) on Tuesday August 05, 2003 @10:46AM (#6615570) Homepage
    Here's one easy thing that you can do to minimize the impact a power supply will have on the internal temperature of your case...

    You'll notice on most power supplies that there is a fan venting heat INTO the case. An easy solution is to reverse the fan(s) in your power supply so that they pull air from inside the case and vent it out the back. This is especially handy when incorporated with a case fan in the front of the chassis that moves cool air into the case. This establishes a nice flow of cool in the front and warm out the back.

    Reversing the power supply fans is usually one of the first mods I make to my PCs when setting up the cooling system.

  • Either I haven't read the comments up to this point carefully enough, or nobody has said anything about line current, and its effect on PSU performance. The article didn't have any tests for it either.

    I know we all power our machines through UPSs with nice clean conditioned power, but most of the unwashed masses plug theirs right into the wall, with all the attendant brownouts, spikes, and neat things that happen during thunderstorms.

    Too bad they couldn't test the performance and robustness of those unit

  • Power Factor (Score:2, Informative)

    by Anonymous Coward
    IMO the biggest problem with most power supplies is the terrible power factors. Power factor is what fraction of apparent power is actually used by the load. Typical PC power supplies have a power factor of 0.5 to 0.6 -- pretty poor. Bad power factor means that fewer machines can operate on a given circuit. PC power supplies and fluorescent lighting are the biggest contributor to circuit overload in office settings.

  • As an example... (Score:3, Informative)

    by phorm ( 591458 ) on Tuesday August 05, 2003 @11:37AM (#6616178) Journal
    I used to run a cheaper PSU in my old "Duron" box. Not, Durons are (or were then, not sure about not) inefficient power-gobbling little monsters, but the PSU was rated such that it should have been more than up to meeting the demands of the chip. However, odd things started to happen. Notably, if I were using both my Burner and DVD-ROM at the same time (i.e. copying a disc), sometime later one of the drives would go offline. The drive would simply cease to exist, and would not be found by the system (didn't eject right either) until I did a shutdown and restart of the system.

    In summer, I also had to worry about my CPU overheating. Since then, I've got a better power supply, and no more CD-ROM malfunction. With the added PSU fan, my CPU no longer overheats in summer either.

    Seriously, if you're going to shell out several hundred for a top-of-the-line video card, or > a grand for a nice system, then at least have the sense to put a formidable power supply in it.
  • I personally, have taken a cheap, no name power supply and changed all the caps in it. result: much better power supply.
    I always crack open power supplies to see what brand caps they use, because I know from experience that its caps failing in power supplies that kill them.....
    and your computer.
    I have seen a brand new brand name power supply use the WORST caps.
    so, you can compare these brand name supplies all day, but there might be a cheap one thats more stable, if not better made.
    shop around, you might be suprised.

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