Is It Worth Investing In a High-Efficiency Power Supply? 328
MrSeb writes "If you've gone shopping for a power supply any time over the last few years, you've probably noticed the explosive proliferation of various 80 Plus ratings. As initially conceived, an 80 Plus certification was a way for PSU manufacturers to validate that their power supply units were at least 80% efficient at 25%, 50%, 75%, and 100% of full load. In the pre-80 Plus days, PSU prices normally clustered around a given wattage output. The advent of the various 80 Plus levels has created a second variable that can have a significant impact on unit price. This leads us to three important questions: How much power can you save by moving to a higher-efficiency supply, what's the premium of doing so, and how long does it take to make back your initial investment?"
The Maths (Score:5, Informative)
new efficiency @ load % - old efficiency @ load % = delta%
integrate over time (delta%*cost kw/hr) until result = new unit cost (solve for t)
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Re:The Maths (Score:5, Informative)
Scenario 1: an always-on computer running near-idle for four years.
Idle power draw, 85% efficient PSU: 66 watts
Idle power draw, 80% efficient PSU: 70 watts
Delta: 4 watts
Total power difference over the four-year life of the computer: 140 kilowatt-hours.
At 5.5 cents per kilowatt-hour (cheapest power in the US), building with a more-efficient power supply makes sense if it costs no more than $7.70 beyond what the less-efficient power supply does.
Scenario 2: an always-on computer running Folding@Home for four years using both CPU and GPU.
Power draw, 90% efficient PSU: 215 watts
Power draw, 80% efficient PSU: 245 watts
Delta: 30 watts
Total power difference over the four-year life of the computer: 1.05 megawatt-hours.
At 36 cents per kilowatt-hour (most expensive power in the US), building with a more-efficient power supply makes sense if it costs no more than $378 beyond what a less-efficient power supply does.
The second scenario represents someone running F@H on a modern high-end computer in Hawaii -- not exactly "unrealistic".
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I'd like to add to the above. It truly depends on circumstances.
If you're trying to be energy neutral or positive in your living (e.g you want to be off the grid with a wind/solar setup) then every efficiency gain will more than offset the cost of producing / storing the power required).
If you're just wanting to view movies / ebay / email an live in a McMansion, with the full home theater setup, then there's no point because the rest of your lifestyle says "Fuck the planet, I'm all right"
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Given that a more efficient power supply generates less heat, does it last longer? And does it generate less noise, since it doesn't need as fast a fan? Which gets kinda importat at the wee hours of the morning.
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But..but...but.. dual GPUs... Well, I can purchase an 8 socket AMD and cross-fire 8 GPUs, but I wouldn't consider that a "desktop". Dual GPUs is like extreme enthusiast.
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Then you dont know much. I run TWO Nvidia video cards and when in full gaming mode I cant exceed 300Watts of power draw. This is real measured numbers, not the fake crap on spec sheets. This is in a low end i7 3.2ghz setup with only 12 gig of ram and 4 WD Black drives.
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The big factor for me is: how much heat does it put out? Texas in the summer can be brutal, and anything to keep my office half a degree cooler helps tremendously, especially in the era of multiple monitors. Higher efficiency = less waste heat.
Re:The Maths (Score:5, Insightful)
Not to mention reduced heat output (and potentially less fan noise due to lower heat), important in many scenarios
Re:The Maths (Score:5, Informative)
Not to mention reduced heat output (and potentially less fan noise due to lower heat), important in many scenarios
Plus you have to add in costs due to the extra air conditioning load in the summer time (gotta remove all of that heat), and subtract in the winter time to account for the fact that your furnace needs to do less work to keep your house warm.
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Re:The Maths (Score:4, Informative)
600W is actually pretty enormous by modern standards. an i7 3770k will use 77W, a very high end GPU 250W, and motherboard and other bits about 50... so even for very very high end systems, you're talking about 400W total consumption with everything under maximum load. Under most normal usage you're talking more like 100-200W.
Re:The Maths (Score:4, Insightful)
That's a meaningless comparison tbh. The difference is likely that of 'el-cheapo' vs 'upper-mid-range'. The el-cheapo is probably not as stable when you get closer to its rated output.
An upper-mid-range 400W would probably have been fine.
Also, a general question on efficiencies; Do the higher power rated PSUs generally have higher efficiencies at lower power outputs? IOW, given 2 comparable model 'high efficiency' PSU's, one rated at 1000W and the other at 500W, would the 1000W one be more efficient than the 500W one at, say, 250W?
That could make the 'over the top' ones worthwhile even at lower power levels...
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If you spend $15 on a PS don't expect it to run long, and when it does go it could be in a big way.
Which also explains all the cheapskate DIYers who say they still get blue screens in Windows XP and above. Windows hasn't been unstable since ME. It's probably power fluctuations or cheap/underrated caps on the motherboard that's responsible for more blue screens than anything these days.
Re:The Maths (Score:4, Insightful)
"Not a major factor"? That 120W spread over a year yields:
120W * (1kW / 1000W) * (24 hours / 1 day) * (365 days / 1 year) = 1050 kWh / year
I just checked my electric bill; I'm paying about $0.14 per kWh. That gives:
(1050 kWh / year) * ($0.14 / kWh) = $147 / year
A 90% efficient PSU is half as wasteful as an 80% PSU, and half of $147 is about $73. If you can pay $73 to upgrade from an 80% efficient PSU to a 90% efficient PSU, you'll get 100% return on investment in one year. That's ignoring the extra cooling demands of the higher efficiency unit (and ignoring the decreased heating demands because electric heat is freaking expensive so $73 in electric heating would offset, what, $10 of gas heat?).
TL;DR: you're almost always better off buying the high efficiency PSU.
More maths (Score:3)
The info I got from the article at http://www.cameralabs.com/PC_Hardware_reviews/Power_supply/Choosing_a_PC_power_supply.shtml [cameralabs.com] is this ---
If your computer consumes X-watts, it's advisable to fit a PSU that can pump out almost 2X the wattage.
Re:More maths (Score:5, Informative)
That was true in the past when the PSU wasn't a particularly valued component and the industry standard method of rating their power output was 'think of a number, any number. Now write that number on the side.'
It's *less* true these days if you're buying from one of the decent brands. The numbers they write on their spec sheets actually bear some kind of resemblance to reality, these days: you can actually accurately spec up your expected draw against the capabilities of a PSU and expect it to more or less work out. It's worth leaving a bit of safety room, but you don't really need 2X.
Re:More maths (Score:5, Interesting)
Yeah, I used to get the cheapest PSU I could. But after I somehow inexplicably fried some of my expensive components, like my GPU, I decided to drop in something a bit better.
When I dropped another $250 on a replacement GPU, I also decided to shell out real money for a nicer PSU and put my old PSU out to the pasture... in my kids' cobbled-together box.
Ended up going with a SeaSonic, since that's one of the brands that tend to be recommended by the Ars Technica Budget / Hot Rod box guide.
I wish I could find it, but there was some PSU snob site that went into all of the power benchmarking and provided pagefulls of data and charts like the other sites that benchmark CPUs and RAM. They managed to point out all the ways my old PSU was deficient and sorta almost turned me into a PSU snob as well.
Re:More maths (Score:5, Informative)
You're thinking of hardwaresecrets.com - they do the type of PS reviews only an EE truly appreciates! :)
Re:More maths (Score:4, Informative)
That brings home another benefit of picking a high efficiency power supply: generally a much higher quality and specs that you can actually trust. For instance compare the review of the Coolmax 750W [hardwaresecrets.com] with that of the Corsair VX450W [hardwaresecrets.com]. The el-cheapo 750W PSU blew up twice [hardwaresecrets.com] after they pulled just 500W while the 450W one managed to provide a stable 572W [hardwaresecrets.com] before it shutdown cleanly due to over load protection! So before buying a power supply it's worth reading a proper review of it, even if you only read the conclusion [hardwaresecrets.com] page [hardwaresecrets.com].
So just looking at much is saved on electricity is missing the big picture.
Re:More maths (Score:4, Funny)
Hey! That's the same formula for calculating swap space! Must bee something deep going on here. :-0
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Re:More maths (Score:5, Interesting)
At home, I run a decent 350W PSU now, and my system draws about 200W of DC power under load (i.e. gaming) with my components (single Intel 2500K CPU, 8GB RAM, ATI 7870 GPU. 1 HDD and 1 SSD) and around 130W when surfing the web or working. I literally couldn't find a decent, well priced PSU with lower DC power output when I built the machine 18 months ago. It cracks me up when I see guys putting 700W power supplies into their gaming rigs that never draw more than 300W (and none seem to understand the difference between AC power draw from the wall and DC power draw of the components in their system, which is what the PSUs are rated for). It's basically flushing money down the toilet in multiple ways.
Just my $0.02...
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It cracks me up when I see guys putting 700W power supplies into their gaming rigs that never draw more than 300W (and none seem to understand the difference between AC power draw from the wall and DC power draw of the components in their system, which is what the PSUs are rated for). It's basically flushing money down the toilet in multiple ways.
About sums it up for me. Time and time again, reviews show "at the wall" power draws for modern non-OC'd, non-dual GPU high end desktops being under 300 watts at peak.
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That's carryover from the bad old days when way too many power supply vendors played fast and loose with the figures. If pushed much over 50% utilization, the supplied power started getting dirty. Couple that with crazy overclocking rendering the system over-sensitive and you really did need the P/S to be rated at double the actually required power.
Re:The Maths (Score:5, Insightful)
Your HTPC server consumes 350W? What the hell do you have in that thing?
Mine consumes less than 65W running full blast, serves files and 1080p video. I'd say you'd save a hell of a lot more money by downsizing that HTPC rather than just getting a more efficient power supply.
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Your HTPC server consumes 350W? What the hell do you have in that thing?
What is an HTPC server? What makes it different from a regular server?
I used to run a 24 disk raid box 24x7 for media-serving duties and it pulled about 350W at steady state according to my Kill A Watt. [p3international.com]
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what makes it different? From a designer's perspective, I would say something that is small and as quiet as possible. In the case of systems I designed, more often than not around Shuttle XPC chasses, fanless. There may have been barely detectable sounds coming from an external water pump running at half speed (although that was shortlived, being as I shortly discovered the joys of Peltier heat pumps and huge copper heatsinks), but the hard drive was insulated so well on rubber dampers and felt lining insid
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I have 2TB drive with well over 2 seasons of 5 different shows (I have 5 seasons of one of them) and it just breached 50%. I think you should probably find out why your video encoding software sucks balls or keep fewer episodes.
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I have 14 hard drives attached to mine and it only draws 180W. I could probably improve that by running a more modern i3 motherboard and better power saving features.
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a diablotek is also likely to die and take your expensive computer with it.
Re: (Score:2, Informative)
new efficiency @ load % - old efficiency @ load % = delta%
integrate over time (delta%*cost kw/hr) until result = new unit cost (solve for t)
You're missing the savings on removing that excess heat from your house too (in climates where that is relevant).
In a cold climate where you are heating your house, unless you can get better $/unit heating out of something else, the "waste" energy is heating the house anyway so it doesn't matter much.
In a hot climate where you are cooling your house, every unit of heat that you put into the house has to be removed. Firstly from the computer by making the fans work harder, then from the house itself by makin
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I'm not an electrical engineer, but I don't believe all waste energy is heat, some of it is probably RF energy that's not absorbed before it leaves your building.
However, in my case, switching to higher efficiency power supplies meant I no longer had to run my air conditioner even while there was snow outside. That's a pretty big power savings.
If it's worth squeezing the last 1-2% is a different question.
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So living in an apartment is "doing it wrong"?
Most of the apartments I've lived in had electric baseboard heating. For some reason the building owners didn't want to let me install my own gas furnace. Maybe I should ask them if I can drill from the 20th floor down to the ground and a bit more so I can install a heat pump.
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So living in an apartment is "doing it wrong"?
In this case, your landlord is the one "doing it wrong." Unless it's you who has to pay the electric bill, then he did it right.
Re:IMG Tag? (Score:5, Funny)
I tried to include an image of the formula using the IMG tag instead of text, but it wouldn't display. :( Any tips on how to include an image in a comment on /.?
I've never seen an image in a slashdot comment before, I think it's for our own safety.
Re:IMG Tag? (Score:5, Insightful)
The real embarrassment is that /. has never supported basic tags like <sup> which would allow proper math mark-up. Instead we get all manner of mangled, unreadable blobs for comments.
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And you can thank goatse.cx for that. I can't imagine looking at that gaping hole a dozen times per day.
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I've never seen an image in a slashdot comment before, I think it's for our own safety.
I remember the good old days before the spam filter when every third post was an ASCII depitction of goatse and we liked it!
... porn and cat pictures ...? (Score:3)
Are you saying this would make /. somehow a lesser site? (scratches head)
I would insert a picture of a naked cat looking quizzical here, but alas, no IMG tag support.
See what you're missing?
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I'll bet... (Score:5, Funny)
Not an investment (Score:2)
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an investment is something that returns more value than it costs.
By my definition, a car that depreciates is an "investment" because with it you were able to get a job and make more than the car cost, even if the car itself was a loss. The power supply is the same. If you count the added cost of an 80% efficient supply, you may never make back the difference, unless you count the air conditioning savings, and put a price on the
Re:Not an investment (Score:4, Insightful)
If you're only factoring just the electricity bill as a factor. But there are also environmental reasons maybe and it's harder to put an unemotional price on that. This is sort of like the people who claim hybrid electric cars are a waste of money since they're only looking at the wallet and not the bigger picture. It's more than just saving a little electricity as well, there is also the slight increase in customer demand, which slightly increases the market forces towards creating more efficient products in general.
Bought one (Score:2)
Bought one Antec Earthwatts long time ago. The PSU was not much more expensive than the others (good brands) so the savings are obvious. Still, the PSU is very quiet which is the main reason why I bought it.
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Bought one Antec Earthwatts long time ago. The PSU was not much more expensive than the others (good brands) so the savings are obvious.
Another thing TFA doesn't take into account is that the 80-Plus certified supplies tend to have better components overall than non-certified supplies.
Read some of the reviews at Hardware Secrets [hardwaresecrets.com] and you'll see that it's not uncommon for a well-built "350W" power supply to be able to output 450W, while a crappy 350W supply can't even handle 300W.
Cooler (Score:2, Informative)
One advantage of a more efficient PSU is that it runs cooler. This is nice at least if you are going for a silent system, as less fans are then required.
Read this and decide for yourself (Score:3, Informative)
http://www.extremetech.com/extreme/143029-empowered-can-high-efficiency-power-supplies-cut-your-electricity-bill/ [extremetech.com]
Turn down the screen brightness (Score:2)
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The power maths... (Score:2)
To make the maths easier, lets assume you can improve your efficiency by 25% (that's huge) and assume you're loading it to 400 watts, (also huge) and assume you run it 8 hours a day, 5 days a week with 2 weeks off a year (running at full capacity).
That's 100 watts of savings, 2000 hours a year... 0.1kw X 2000 = 200kWh per year.
I pay about $0.10/kWh
You could save up to $20/year.
Reality? You'd probably see a lot less savings then that.
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Okay, "up to" only applies if you are computing using reasonable maximums, which you aren't. $20/year is a reasonable estimate, but not "up to".
25% efficiency improvement is pretty big. 400 W is a large load for some machines, but isn't that huge a load. $0.10/kWh is actually substantially below the US average of $0.12/kWh.
The biggest variable factor here, though, is computer uptime. Hugely variable. My home PC probably sees 500-800 hr/yr use. My work PC probably sees your estimate of 2000 hr/yr. My HTPC is
Quieter and cooler (Score:4, Interesting)
Higher efficiency means less waste heat coming from the power supply, so its fan can run quieter.
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And from an AC we have the best answer. A cheaply made power supply can much more easily damage your computer's other parts. Factor in the cost of replacing them and the more expensive power supply pays for itself regardless of energy savings.
Waste energy is converted to heat (Score:3, Insightful)
Saving a few bucks on electricity is hardly the only reason to buy a more efficient power supply.
- Jesper
that isn't the logo to be looking at (Score:2)
don't choose a cheap piece of shit just because it claims a higher '80 plus' certification level than a quality, name brand unit from a reputable company that might cost twice as much.
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don't choose a cheap piece of shit just because it claims a higher '80 plus' certification level than a quality, name brand unit from a reputable company that might cost twice as much.
yeah, this hits home. I just replaced my second failed Rosewill 80+ today (5-star reviews...). Visible build quality on the first two were great, but obviously the guts aren't so good. I'm gonna open it and look for mushroomed caps.
The third one, my only spare-on-hand is of such poor build quality that the metal conductors
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Yeah Antec is good generally, most of their stuff is made by seasonic. So is OCZ(generally), mushkin, and a few others. I'd recommend looking through here. [hardwaresecrets.com] And see who is making what it can change sometimes between revisions. And generally the reviews are quite good. And each PSU has a teardown, including what's being jammed inside the guts. So you have a fairly good idea of what components are being used.
Quality, noise, heat... (Score:2)
These days, 80plus PSUs are very cheap. The only things cheaper are unreliable JUNK PSUs which won't last a year. Also, because of the legal terms of using the 80plus trademark, manufacturers seem to not inflate the wattage ratings on 80plus PSUs, while you can easily find $15 "2000watt" junk PSUs.
And besides all that, I'd pay the 80plus premium just for the heat/noise reduction. Combine with a WD "Green" hard drive (or SSD), low-power CPU, and a couple low-noise fans, and you've got a very low heat and
Save more by buying small (Score:4, Informative)
A PSU has a power efficiency curve that looks like this [anandtech.com]. That article also explains what I'm about to summarize:
Pick a PSU that is no more powerful than you need, to keep your system in the middle of that curve, for maximum efficiency. 100% margin is more than plenty, so if your components will use 250W max, you don't need a 900W PSU. Look for something in the 500 range, or even less if you pick a good-quality PSU.
You probably won't be able to make a cost argument for maximizing efficiency, but you can build a quieter system focusing on efficiency, and it's quite satisfying obsessing over something different.
Match Your Power supply to System Power Reqs (Score:2)
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It depends a lot on whether "about 350 W" is a maximum or an average and even more on what you've been doing with your computer while you measure. Measuring draw like that is a good idea, but it doesn't tell you everything. There very well may be usage patterns for components in your system that some software may cause that are higher than your normal usage. If you start using your computer a different way (say by running a demanding game which uses your CPU, hard drives, optical drives and gpu hard all at
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All switch-mode power supplies are 0% efficient at 0 load.
Re:Match Your Power supply to System Power Reqs (Score:4, Informative)
If you look at efficiency graphs, you'll see that power supplies are typically the most efficient under moderate load: at low and high load the efficiency drops. A typical desktop or home server is idle most of the time, so idle efficiency will have a big impact on the total efficiency. If you over-dimension your power supply, your idle load might be 10% or less of the max rating, which is far from the optimum of the efficiency curve.
I'd recommend getting a power supply that can deliver a bit more than what you need, for example 450 W if you think you need 350 W max. A bit of margin is useful since you might not have found the actual worst case or you might want to add components later. Also it avoids poor efficiency at the high side of the curve when the system is under load.
No. (Score:2)
It's not just the power (Score:3)
Noise is also a factor. High-efficiency supplies have fans that run more slowly under load, or not at all. If you're building a quiet system, this is a big deal.
Note that the peak efficiency is usually at ~50% load, so be sure to size your power supply appropriately for best results. Newegg has a calculator [newegg.com] to help with this.
Re:It's not just the power (Score:5, Informative)
Newegg's calculator is a joke. It drastically overestimates requirements so they can pimp massive PSUs with higher profit margins. I suggest adding up the various component manufacturer specifications (i.e. max power draw of the MB, GPU(s), HDD(s), DIMM(s), and CPU(s)) and throw in 10-15 W for overhead, then buy a decent PSU with a load rated as close to that number as you can get. Even with a dual GPU setup, you are VERY unlikely to exceed 400W of DC power draw. My current mid-range single GPU system draws around 200W under load (gaming).
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Disagree about peak efficiency. In my experience testing PSUs, it is normally found around 90% load. Newer PSUs have gotten a lot better and enhancing efficiency at lower load levels, but PSUs still work most efficiently when running near the load they are designed for.
Thank you for the correction. I was talking based on the 80+ certification requirements and hazy memory of an article I saw once. Glad you know the efficiency picture is better than I thought.
Choose a lower power PSU if you can (Score:2)
Unless you really need it, then choose something more modest than a honking 1000W PSU. Not a frag-fracking gamer? A 90W DC PSU should have enough juice for your 65W CPU. As PSU efficiency is measured in percentage, even a 50% inefficient 90W PSU will beat a 95% efficient 1000W PSU.
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My experience is that nearly everyone overestimates their PSU needs and it becomes a game of "who's is bigger?". This is a stupid way to pick hardware. My desktop runs a 650, my ESX server with 24+ bays runs an 850. If I had a way better video card in the desktop I might move to a 750 and I wouldn't run dual cards.
My HTPC with ion chipsets use 9-16 watts at the wall at 100% usage.
not worth buying new psu for ..but (Score:3)
so it probably for 99% of the people won't make sense to upgrade a power supply just for efficiency
but if for some reason you need a new power-supply anyways finding a good quality (80+ gold ..etc) unit on sale is totally reasonable.... at this point most units worth trusting the rest of your gear to are probably 80+ anyways.
in my own case i had been using a 80+ power-supply that wasn't modular and cables where a hassle to manage ... i wanted a modular power-supply and also have no intention of risking a $200 processor and $300~ video card etc to a generic / shoddy power-supply so i found the Seasonic X750 (80+ Gold ) on sale for $100~ (which if you look at newegg is cheaper than any 700-800watt fully modular power supplies currently.
since i wanted/needed fully modular 750~ish watt power-supply finding the X750 for $99 made sense as it was cheapest meeting those requirements.... the fact is it 80+ is just bonus ... seasonic's 5year warr and generally pretty good reputation for quality power supplies drove the choice more than the 80+ gold.
It's not just about effeciency... (Score:2)
The design choices that manufacturers make in order to meet these levels of effeciency have other impacts. Active power management, cooling fans that only run when needed, and higher quality components are all good reasons to consider a higher effeciency rated PSU. My computers often run 24x7 for years on end so I tend to choose decent PSU.
Also, just as a data point, I have a 4U box running a Xeon, 32gig of RAM, many cooling fans, 3x SAS cards, an SSD, and at least 20x HDD. It has a gold rated PSU listed as
Discriminating the junk "factor" (Score:2)
Most PSU that do not sport the 80+ badge are outright junk that does not respect environmental and security norms in the first place, and will blow up in a variety of creative ways if you were to draw half of what is written as max wattage on the sticker. The 80+ badge weeds out most of the crap (not all though).
GlobalWarming@Home (Score:2)
I've been wanting to start a project; 'GlobalWarming@Home', with client software for people who want to contribute to the global warming effort.
All it would do is run your CPU/GPU full tilt, using as much power as possible to 'contribute' to global warming.
my $0.02 (Score:2)
I bought a midrange power supply (Antec Gold £150 job) for my gaming rig some years ago (it was an Athlon XP2400+), which said 750W on the box. With a 4-box RAID0 and GeForce 7600GT the power draw was something like half that. It's still running.
I built an identical box around the same time for someone else. He didn't see the point of a beefcake PSU so he said to use a cheap (read: £20) 350W brick. His computer lasted a month before the caps blew and took the motherboard with it.
For me, it's le
Money isn't everything (Score:2)
If people use less power through more efficient devices there needs to be less power produced. Less power production means less pollution and less greenhouse gases. Environmental issues may be a contributing factor in the selection of a more efficient power supply.
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Not everyone is polluting by consuming electricity. Pretty much all of the power I use comes from hydro.
You forgot a variable (Score:5, Insightful)
(1.) Not die within a year of running at 50-75% load
(2.) Not take any other components of my computer with it.
Power supply problems are the most annoying to diagnose, because the symptoms usually show up in other components (like apparent RAM corruption, HDD stuttering, etc). I would pay $50 extra for a power supply that is *not* 80-plus if it has stellar reliability, because it means I only have to build my computer exactly once. On that note, the Corsair HX [newegg.com] series power supplies have not only stellar reliability, but also pretty much silent. I refuse to buy anything else, and you can usually them 20% off if you watch slickdeals.
Efficiency saves you money, while reliability saves you time *and* money. And time is a limited resource for some of us...
Quality factor (Score:2)
Silence is 80+% golden (Score:3)
Comment removed (Score:5, Interesting)
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Can you really qualify heating done with heat pumps as electric heating? My house is heated with hot water from a gas furnace recirculated using an electric pump. By your definition of electric heating, wouldn't that make my house electrically heated? Also, aren't there transportation and conversion losses from burning something for heat just as there are with electric heating?
And in the summer, if the AC is on, inefficient appliances make you lose double: once by consuming more electricity than they should, and a second time because the AC needs to consume energy to pump the heat out of your house.
I'm not sure what method you can possibly imagine for pumping heat out of your house that doesn't consume energy.
Re: (Score:2, Informative)
This is why "software engineer" is a term I will never use willingly. It is an insult to real engineers. Heat pumps do in fact put more heat into their hot side than they consume in work. They take heat from a low temperature resivoir and send it to a high temperature resivoir.
Comment removed (Score:4, Informative)
Re:Do you heat your house? (Score:5, Insightful)
Perhaps the "pump" part of heat pump completely eluded you, since they do not defy the first law of thermodynamics as you seem to be implying.
Heat pumps work by having a sink source off of which they are pumping the heat from or away from. Most of the ones I know happen to be geothermal, which work because the sink which they are pumping from maintains a constant temperature year long underground. So, during the summer, the heat they can extract from that source would be cooler than the air above ground, but during the winter be hotter. They do this by extracting the heat from the source sink, rather than producing it themselves.
So in that respect, they work much like the fan does within your computer, since the air inside the case is much hotter when running than the air outside of the case. The fan can then displace that heat generated inside rather efficiently by just pushing the hotter air inside the case out, while bringing the cooler air from the room outside in without having to require an equal amount of energy to then power those fans as the equipment running inside of it, thus, like the grandparent, requiring less electric energy to power those fans than what the computer itself uses. If this were not so, then it'd make a lot more sense to completely seal computer cases, as the cooling benefit from the fans wouldn't make up for the amount of dust which they bring into the case during operation.
So the next time you're tempted to call bullshit on a well known physics principle, make sure you double check that you're not making some stupid mistake. Or else you'll end up looking rather foolish again when someone else points out how you don't know what you're talking about.
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Well technically the waste heat from a power supply is 100% efficient. Any inefficiencies from it producing heat are used to power the computer.
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Even compared to a 400%+ efficient heat pump? The heat pump in my lounge puts out 4.4W of heat for every watt it consumes.
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Corsair's AX850 is a solid power supply OEM'd from Seasonic. But you can't cost justify buying one unless you have a truly ridiculous system. As of a few years ago, a good 500W power supply was already plenty to handle even three video card systems [tomshardware.com], and CPUs in particular have just reduced power requirements since. Newegg is showing me the AX850 as $189. You can get their similarly constructed 650W TX650M instead for $109. I was willing to pay whatever I had to in order to get the most reliable setup p
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