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Part 2: Four Cheap 80 PLUS Bronze Power Supplies, Reviewed

Part 2: Four Cheap 80 PLUS Bronze Power Supplies, Reviewed
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Ready for part two of our low-cost power supply round-up? Here are four more products, including Seasonic's SSR-360GP, which is 80 PLUS Gold-certified. Is this little 360 W PSU the bargain of the century, or is its Gold label simply pyrite?

Part one of our budget power supply round-up debated the merits of four PSUs ranging from 350 to 550 W, all of them flashing 80 PLUS Bronze ratings. Aside from the Cougar A350, all of them proved capable of satisfying the specification. Today we're looking at four more power supplies, this time ranging from 360 to 550 W. The range is a little narrower, but the contenders are all still quite comparable. Three sport the same Bronze logo, but one, Seasonic's SSR-360GP, boldly claims compliance with 80 PLUS' Gold standard, typically reserved for £80-plus products. All the while, the SSR-360GP sells for well under that.

Although that aggressive price gets our attention, we aren't going to neglect the other three test candidates: Cooler Master's Silent Pro M2 520W, Corsair's CX500, and Gigabyte's Greenmax Plus 450W. That Gigabyte unit doesn't seem to be available in the U.S., but with 550 W and 650 W versions showing up on Newegg, we're hoping to see the 450 W model soon.

As with yesterday's story, we again asses the sound levels of each PSU. This is something readers have been requesting for a while. Until now, though, we lacked a practical and reproducible methodology. From now on, we'll be measuring acoustics at three load levels: 40 W, which simulates an idle PC or a machine running office applications; 200 W, standing in for a mid-range gaming workload; and a 600 W draw to replicate what a more extreme gaming PC might encounter with a couple of graphics cards installed. That should get each unit's cooling fan spinning as fast as possible. Of course, if 600 W exceeds the maximum output of a power supply, we made do without it and simply use the other two.

In order to simulate these loads, we built a test fixture consisting of 12 V/40 W light bulbs, which imposes a purely resistive load on the power supply. With 15 lights, we can simulate any load between 40 W and 600 W, in 40 W steps. We are aware of the fact that a purely resistive load may stress a power supply differently than the partly capacitive, partly inductive load of a real-world PC. But we’re not overly worried; this synthetic load should be perfectly suited for measuring the sound level of the PSUs at each load level. Acoustics are measured one foot away from each power supply's fan, and we let each unit settle for half an hour any time we change the load.

Note that, in part one, we talked about a unique anomaly exhibited by one of our instruments. In short, after we upgraded oscilloscope probes to better ones, all of the PSUs we tested started showing spikes that the previous, less expensive probes never displayed. After some back-and-forth with a couple of power supply vendors, we came to the conclusion that our new probes allow us to pick up short spikes that the old ones missed.

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  • 0 Hide
    hefox , 29 August 2013 10:05
    This looks like clear publicity for Cooler Master. You've tested it against PSUs that can't be even compared like Seasonic 360W and Gigabyte. The only one comparable is Corsair. Why didn't you compare it to Seasonic M12II-520 or SS-450RM which has more or less the same price or XFX 550W or Be quiet! 530W? Don't bother to answer, it was just a rhetorical question.
  • 0 Hide
    SR-71 Blackbird , 29 August 2013 16:21
    Seasonic!!!!!!!!!!!!!!!
  • 0 Hide
    virgult , 29 August 2013 16:49
    That Seasonic looks like the quiet PC's dream.
    Also, Tom's, can you give more details about the sound measurement methodology? E.g. distance, ambient noise, ambient characteristics...
  • 0 Hide
    satrow , 30 August 2013 01:15
    The little Seasonic is a beaut! Very capable and quiet, makes a nice ITX general-purpose/gaming rig, had one in my Prodigy/Xeon build for 5+ months now.

    http://www.3dmark.com/3dm11/6571014
    http://www.passmark.com/baselines/V8/display.php?id=12328227685
  • 0 Hide
    AGTDenton , 4 September 2013 11:53
    I don't see how the reviewer favoured Cooler Master at all, I saw 3 very competitive PSU series where the decision on which one to get would lie with the builder and the requirements of the computer being built/upgraded. There's only 1 model that I would not consider.

    Very happy with my Seasonic G-650 Modular except for the cable length. I only built it with a mATX tower and some of the cables are far too short even without attempting any cable management. So god knows how it would fair with a standard ATX tower chassis.