5-way High-End 1KW+ PSU Round-Up

Test Results - Voltages

Test Results - Voltages
When examining the performance of a PSU under load it is often all too easy to get tied up in the output voltages rather than  how stable the unit actually is. For example: PSU 'A' might have an idle voltage reading of 12.2v and a load reading of 11.9v whereas PSU 'B' might output 12.0v at idle and 11.8v under load. Common sense would tell us to opt for PSU 'A' as under load it outputs the voltage closest to our ideal +12.0v. However, while this is most certainly carries some weight. PSU 'B' actually exhibited less fluctuation between idle and load voltages, indicating that it is better equipped at coping with the stress of a heavy load.
For this reason, when viewing the graphs below we will not only be assessing the how close the voltages are to +12.0v under load, but also how flat the line is between 50% and 100% load depicting the stability of the unit.
Starting off with the +3.3v rail both the Cooler Master and Corsair units manage the least fluctuation between 50% and 100% load voltages. However, for some reason the Corsair unit seems to have its +3.3v rail voltages set a lot lower than the rest of the units in the test, with voltages as low as 3.2v being produced under full load.
The Be-Quiet and Silverstone units show the greatest dip in 50% and 100% load voltages, indicating that their +3.3v rails aren't quite as strong as the rest of the PSU's in this test.
Moving on to the +5v rail we can see that most of the results run in an almost parallel downward fashion. However, the Enermax unit doesn't seem to take kindly to the increase in load from 75% to 100% with the voltage dipping from 4.96v to 4.89v. Of course, this is still well within specification, but its certainly not as strong as the other units.
In the +12v1 and +12v2 results the most stable units are the Enermax and Silverstone, with both exhibiting little change in voltages from 50% load to 100% load. The unit with the largest visible fluctuation between light and heavy load is Corsair unit, which produced a flat line between 50% to 75% loads and then takes a rather sharp downward slope once 100% load is applied.
At the bottom of the chart is the Be-Quiet unit, which starts at a fairly reasonable 11.9v under 50% load, but then takes a fairly large drop down to 11.77v which would probably send the overclockers among us running for the hills.
On to the +12v3 and +12v4 rails and we are dwindled down to four contestants. Once again the Be-Quiet unit is sitting at the bottom of the pack with voltages as low as 11.68v under 100% load, while at the other end of the scale, the Cooler Master and Enermax exhibit the least voltage fluctuation overall.
Despite the fact that both the Enermax and the Silverstone unit are spec'ed as having six (albeit virtual) +12v rails, Enermax's Chroma 6310 only allowed for testing on four of these rails. However, both the Be-Quiet and Cooler Master units that were sent to Germany for testing on a Chroma 6000 had loads applied to each of their six rails.
As we can see from above, the Cooler Master unit produced the more stable voltages of the two units with a slightly straighter line between 50%, 75% and 100% loads. Once again the voltage output of the Be-Quiet unit under 100% load was very low, coming in 0.20v below the Cooler Master.
While not as important as the primary +3.3v, +5v and +12v rails in a PSU, the+5vsb rail is responsible for providing power to components such as USB Input Devices and Network cards while the PC is in standby mode. PSU's failing to provide enough voltage to this rail could prevent devices such as USB keyboards from functioning and allowing the system to be resumed from standby with a keypress.
As we can see from the chart above, the Corsair and Silverstone units provide the most stable voltages here between 50% and 100% load levels, with other units experiencing slight fluctuations (exaggerated by the graphs scale), but certainly nothing to worry about.
Negative voltage rails such as the -12v and -5v rails were introduced back on the original IBM PC standard PSU's and have decreased in terms of viable usage over the years. As a result the -5v rail was recently dropped from the latest PSU's when  the ATX 2.01 standard was introduced. However -12v remains, and despite its questionable usefulness the above graph shows how each PSU performed when a small load was applied to this rail.
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Most Recent Comments

03-10-2008, 09:03:52

"Looking for a new 1kw+ PSU? We test Be-Quiet, Corsair, Cooler Master, Enermax and Silverstone's latest and greatest units on the most sophisticated equipment."


5-way High-End 1KW+ PSU Round-UpQuote

03-10-2008, 09:19:16

Great round-up review Jim. Shame about the Be-Quiet though, was really hoping for great things from them Quote

03-10-2008, 09:34:14

WC Annihilus
Mmm... I got one of those CM UCP 1100W that I won at Nvision sitting in a box brand new. Really need to get around to selling it >.> Maybe linking this review will net some interestQuote

03-10-2008, 09:34:27

The Corsair HX 1000W looks brilliant.

Nice review, enjoyed reading it. Quote

03-10-2008, 11:14:34

Ooh, that enermax looks nice!Quote

03-10-2008, 11:22:35

Originally Posted by name='teknokid'
Ooh, that enermax looks nice!
Hope you mean the revised version


03-10-2008, 11:38:02

they all look rather nice

but isnt 1k overkill for all but the highest of high end systems now? Quote

03-10-2008, 11:39:05

Originally Posted by name='Jim'
Yeah :P

Its quite a design change, but does look pretty awesome.. Nice review Quote

03-10-2008, 12:07:13

I like the look of that revolution ^^. Only thing is, my PSU sits at the top of the case, so it would look a bit stupid to have the writing upside down. Is it t'other way up on the other side?

Nice review tho, but real shame about the be-quiet, at least there are some really good alternatives now.Quote

03-10-2008, 13:46:25

Nice review. The link for the PCP&C TurboCool on the first page is broken tho, it takes u to the Silverstone Zeus 750W review. I don't think I will need one of these PSUs until 2000W is the standard for extreme high-end with the hardware I tend to use lol.Quote

03-10-2008, 15:18:01

Seriously good review. U just dont see these sort of tests done enough. Saw some old tests similar to this that came to the conclusion that power ratings were extremely exaggerated (the spelling thing says I spelt it right ??). That was b4 we had efficiency ratings and such standards. Reaching 1kw on a cold day in a lab once, no longer cuts it.

I'll post a few exceptions I have:

  • I wouldnt 'con' the Silverstone psu for being longer. If u have a smaller case with this psu - theres other wrongs being committed.

  • I'd like to massage into the graphs the +/- lines that the ATX standards perceive for the voltage levels. If a psu varies a fair bit, but remains within that +/- by a %, I think that's another criticism of the units.

  • If u dont have 4 way sli or 20 hdd and everything overclocked, including the usb line, I want a serious answer as to why u have a 1kw+ psu. Yet alone paid over £150 for it. £150 is a good mark up for Corsair. The Silverstone is massively priced.

Cut the price on the CoolerMaster one and it'd be awesome over-poweredness for the price. Corsair seems to be the banker tho.


04-10-2008, 15:25:24

Fantastic review as usual Jimbo, some sexy PSU's there and just goes to show that OC3D REALLY tests stuff Quote

04-10-2008, 18:33:46

fantastic comparative review, i was a little disappointed by the be quiet mind. wish you'd written this a month ago Quote

04-10-2008, 18:39:02

Originally Posted by name='ionicle'
they all look rather nice

but isnt 1k overkill for all but the highest of high end systems now?
Yea unless youre like me and are developing a peripheral toaster that runs off the PSU Quote

04-10-2008, 19:00:02

Originally Posted by name='llwyd'
Yea unless youre like me and are developing a peripheral toaster that runs off the PSU

"the USB toastomatic" Quote

05-10-2008, 10:22:57

haha, What sort of equipment is used to test psu's?Quote

05-10-2008, 10:49:44

Originally Posted by name='teknokid'
haha, What sort of equipment is used to test psu's?
If you actually read the review it tells you...Quote

05-10-2008, 11:36:16

Originally Posted by name='Ham'
If you actually read the review it tells you...
ooh, I only looked at the end and the enermax revolution :SQuote

05-10-2008, 16:13:33

Originally Posted by name='ionicle'

"the USB toastomatic"
How did you get hold of my secret latest invention plans? That was due to be unveiled next year...Quote

07-10-2008, 16:34:37

Hah you guys crack me up some times.. seriously

Great review, not that I'll be in the market for a PSU like that for a long time but it is really worth knowing that kind of information. Nicely tested, shows (as stated before) OC3D really go to the inth degree to test and make their reviews as accurate as possible!

Thanks guys Quote

08-10-2008, 05:21:56


Well powerfull PSU's needn't run on max to provide the juice needed and hence can run cooler... But ..


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