Debunking Power Supply Myths
by Christoph Katzer on September 22, 2008 3:00 AM EST- Posted in
- Cases/Cooling/PSUs
PSUs for Midrange Systems
Our midrange system opens up a lot more in the way of potential power supplies, as there are far more manufacturers building 400W to 500W PSUs. Our idle power consumption in this case is 168W, which is quite high when compared to the 120W a high-end system would have used a few years back (i.e. AMD Athlon 64 4000+ and NVIDIA GeForce 7800 GTX under full load). However, times change and we see increased power requirements along with performance improvements.
Our selection of power supplies uses the same criteria as before. We will also see how our entry-level power supplies and all this sort of system.
- Cooler Master Silent Pro (500W) actively cooled
- Corsair HX520W (520W) actively cooled
- Corsair VX450W (450W) actively cooled
- Enermax Pro82+ (585W) actively cooled
- Enermax Pro82+ (625W) actively cooled
In terms of efficiency as well as the ability to supply sufficient power, all of the power supplies are able to run this midrange setup except for the 300W Thermaltake unit. The Antec Earthwatts has been around for a while, so it's not surprising that it doesn't perform as well as newer models, but it still delivers decent if not great efficiency. Noise levels are a different matter, and we would be inclined to avoid most of the entry-level PSUs. If noise isn't a consideration, all but the Antec will work; however, the Corsair VX450W performs best out of these units in so we will carry it along to the next level and include it with the midrange offerings.
Efficiency is Not the Issue
With the addition of some higher performing power supplies, efficiency clearly shouldn't be the overriding concern for a computer like our midrange system. The Corsair VX450W doesn't look as good in this graph, although 83% efficiency certainly isn't anything to cry about. The newer models all reach efficiency of around 85% to 86% throughout the midrange system load. Comparing the two scenarios, outside of PSUs that simply can't provide enough power it's not necessary to move up to a higher performance power supply. You want to look at other aspects such as features, warranty, and noise levels before making a decision.
In terms of noise levels, all of these units perform very well and can provide a quiet computing environment. We also see a clear separation between the entry-level PSUs in the midrange PSUs in this chart, since the midrange units are running a 75% load at worst. Again, if you've had the mindset that 600W and higher PSUs are required for modern midrange systems, the above charts should help dispel that myth. If you can find a good quality 400W PSU, it can easily power a midrange system. However, 500W PSUs generally make the best fit, as they provide optimal efficiency and lower noise.
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Dancer - Thursday, October 22, 2009 - link
On the face of it, this article seems an excellent, well-researched contribution to a highly vexed question. I do have a concern, however: We know that the power output of a PSU drops as it ages. We also know that this drop depends partly on quality and partly due to random chance. If I'm buying a PSU to last 3, 5 or more years, will this seriously affect the capacity of the PSU I should buy for a given machine?internetrush - Saturday, June 6, 2009 - link
Ok, lets low ball it, im running 200w (average) per graphics card, about 50w cpu (core i7) and three hard drives.Lets see
200 x 2
+50 + 50 (motherboard chipset)
+30 Sound card
+10 cd drive
+20 (fans)
During a game, much less a stress test, im lowballing a 600w load on my PSU.
If i had an 800w PSU that would be 80% of its total output, which thereby increases its heat and decreases its life.
When you buy a 1000w PSU, not only are you ensuring that you will never watch your computer go up in smoke (had a friend do that to a 350w on an old P4) but you are also not having to replace it whenever you buy a new processor or add something to your system.
This article is good, however, on a tech website i would expect a bit more consideration for the higher end gamers and common sense.
Common sense says, if you are a higher end system user, you WILL expand said system!
For gods sake! Some cards today use up to 500w power (the 4890X2 and new 295 SuperCard).
As a gamer, id rather have a 2000W PSU that id never have to replace than a 400w that would FRY as soon as i threw on a new video card.
Christoph Katzer - Saturday, August 8, 2009 - link
Sorry for the late reply.You are probably right when you see it from the perspective of a high-end-hardcore-gamer... But do you know how small the percentage of people is who actually own a real high-end system?
JohnMD1022 - Sunday, March 15, 2009 - link
It would be nice if you could periodically update this with newer components.lopri - Tuesday, April 28, 2009 - link
BillyBuerger - Sunday, October 26, 2008 - link
Anyone have any info on that Thermaltake QFan 300? That thing looks great efficiency wise. Not normally a Thermaltake fan. And the fan controller looks like it sucks. Just keep it below 150W... Or fan swap.Christoph Katzer - Thursday, October 30, 2008 - link
I will have a review up soon!Cincybeck - Tuesday, September 30, 2008 - link
Couple of "knowitall" friends were trying to tell me I was going to need a larger power supply when I built my new system. Which in turned incited the Microcenter sales person saying oh yea you're probably going to need that too. I turned around said I estimated these parts to draw at most around 200, 250 watts, and I have a 500W Seasonic M12. Shut him up pretty quickly, but my friends were still pushing it the whole way home. So now if they ever bring it up again I can print this article and shove it in their face. Thanks =D0roo0roo - Sunday, September 28, 2008 - link
i like the graphs:)keep it up!
this is the info we need!
normally the psu market is just lousy because of the lack of any real information.
mark84 - Friday, September 26, 2008 - link
For those quoting that old link for the AtomicMPC graphics card power thread, the new/current one is being maintained here http://forums.atomicmpc.com.au/index.php?showtopic...">http://forums.atomicmpc.com.au/index.php?showtopic...