A good power supply doesn't just provide you with ample output. Increasingly, vendors have put a bigger emphasis on delivering power more efficiently, too. We're testing five 80 PLUS Platinum-rated power supplies in the 550- to 600-watt range.
While Citius, Altius, Fortius, or faster, higher, stronger is the motto for the Olympics, the PC power supply market also follows this adage fairly religiously. Manufacturers continue to leapfrog each other by enabling increasingly higher outputs to cope with the most aggressively overclocked CPUs and multi-card graphics configurations drawing hundreds of watts.
It gets bad enough that a cyber-stroll through Newegg or TigerDirect gives you the impression that power supplies under 500 or 600 W aren't even worth looking at. After all, if a fairly affordable card like the Radeon HD 7950 requires at least a 500 W PSU, according to AMD, then adding an overclocked CPU and some storage necessitates even more, right? Fortunately, even as the power supply vendors crank up output, they're simultaneously improving the efficiency of their highest-end offerings.
For this round-up of efficient desktop power supplies, we asked power supply manufacturers to send us their 80 PLUS Platinum-rated products at the lower end of the output spectrum. We set the upper limit at 600 W. Any lower and the number of contestants would have been too small. Our objective was to help system builders find an efficient solution for single-graphics card gaming and other moderately-demanding applications. Five companies submitted samples: the Antec EarthWatts Platinum 550 W, Cooler Master Silent Pro Platinum 550 W, Enermax Platimax 600 W, Kingwin Lazer Platinum 550 W, and Rosewill Fortress-550.
Naturally, the 80 PLUS Platinum rating costs more to procure. But although the output of our five test candidates only varies by 50 W, their price differences turn out to be quite a bit more significant. The list price of Antec's unit is only $120, the Enermax asks you to pay as much as $190! The Cooler Master and Kingwin power supplies are both listed at $170, while Rosewill's sells for $140. Keep in mind that we're citing each manufacturer's suggested price; the actual prices of these power supplies are often up to 20% lower.
- In The Power Supply World, Gold Paves The Way For Platinum
- Antec EarthWatts Platinum 550 W
- Results: EarthWatts Platinum 550 W
- Enermax Platimax 600 W
- Results: Enermax Platimax 600 W
- Kingwin Lazer Platinum 550 W
- Results: Kingwin Lazer Platinum 550 W
- Cooler Master Silent Pro Platinum 550 W
- Results: Silent Pro Platinum 550 W
- Rosewill Fortress 550
- Results: Rosewill Fortress 550
- Test Setup, Hold-Up Time, And Inrush Current
- Efficiency (According To The 80 PLUS Spec)
- Efficiency (Based On Performance Profiles)
- Which Platinum-Rated Power Supply Should You Buy?

and i was making popcorn.
and i was making popcorn.
Pleasant read, though, I like PSU reviews.
they asked for vendors for the PSUs. Theres the offshoot chance that seasonic declined the offer. On other sites, the 520w fanless seasonic unit was compared to Rosewill's 500w silent night unit. The seasonic unit I believe in that review barely edged out a victory.
I believe this is still applicable to all of the power supply testing our German team does: http://www.tomshardware.com/reviews/psu-test-equipment,2657.html. I'm waiting for confirmation that I'm right.
Edit: Yup, that's the correct testing equipment/procedure!
Why is the 80 plus spec officially test by having more load on the 3.3v and 5v rails?
Clearly loading the 12v rail would give us a better overall image
Never mind I see the ripple data buried in the individual tests. It would have been better in the summary side-by-side tests.
Nice article.
Sorry!
The page you requested couldn't be found
fix'd that for ya
Sorry, take the period out of the end of the URL.
Your priorities are obviously backwards. Rosewill's entry, by your testing, failed to meet ATX spec by producing an unacceptable amplitude of ripple on the 12V rail. By definition, this is a fail. This isn't a minor flaw, this is violating spec. A failure can not stand out from the crowd (at least in a positive sense). Now, there are other posters here that dispute your results, but you don't have that luxury. Both your results and summary comments indicate that this unit is a failure no matter how good the efficiency, price, or other metrics look.
You can argue the importance of efficiency versus DC output quality all you want when the unit meets spec, but all of the components in your system rely on PSUs to actually meeting spec in order to function properly. Without meeting spec, there is no way to guarantee components will work properly. In fact, failing to meet spec pretty much guarantees that some component somewhere will not work properly. I've seen enough devices (granted poorly designed) fail to work properly with PSUs that had ugly DC quality, but were technically within spec to recommend one that is out of spec.
Also, the difference in cost between the Gold and Platinum rated models seems to negate the power savings one would realize by going with a Platinum model. Since I do run a few of my machines 24/7, I am curious to see where the efficiency lies for low power consumption for a variety of 80+ certified models as this level of power consumption occupies a large majority of the up-time (70+%).