550W Roundup: Three PSUs at Different Prices
by Martin Kaffei on October 28, 2010 4:00 PM ESTTechsolo Noise Levels and Efficiency
| Sound Pressure Level | |
| Load | dB(A) |
| 10% | 22 |
| 20% | 23 |
| 50% | 28 |
| 80% | |
| 100% | |
| 110% | |
Wow! Our "silent" fan is moderately loud and hit nearly 30dB at 50% load, but even worse is the PFC-choke that's singing like a castrated dog. If you want to have a silent computer, please buy another power supply and protect your ears.
Efficiency and PFC
| 230VAC, 50Hz | ||
| Load | Efficiency | PFC |
| 10% | 68% | 0.490 |
| 20% | 74% | 0.505 |
| 50% | 73% | 0.556 |
| 80% | ||
| 100% | ||
| 110% | ||
| 115VAC, 60Hz | ||
| Load | Efficiency | PFC |
| 10% | - | - |
| 20% | - | - |
| 50% | - | - |
| 80% | ||
| 100% | ||
| 110% | ||
The efficiency hit a maximum of 74%, with under 70% at low load. There is no real power factor correction on display, and we're nowhere near 80 Plus certification. Passive PFC should be good enough to reach 0.700-0.800, but we only hit 0.55 before the PSU died.
Hopefully we've managed to convince you that if nothing else, getting one of the ultra-cheap power supplies is not something you want to do, particularly if you plan on running at anything close to the rated output. Our "550W" unit was able to function as a low-quality 275W PSU before giving up the ghost, but the 73% efficiency at that load means we're wasting 100W of power. Even a basic 80 Plus PSU would save 30-40W, which means if you're using the PC eight hours per day you would make up the difference in price within two years—and that's not even taking into account the cost of replacing hardware should the unit kill your other components in a fit of rage. In short: stay away, because this Black Mamba is poised to strike (and not in a good way)!
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Phaedrus2129 - Friday, October 29, 2010 - link
Except many of the highest-quality units are only of moderate weight due to requiring fewer components; and some of the crappiest units are now being sold with iron weights inside to make them heavier.Weight is a very poor test, actually opening the power supply up and looking with a critical eye is a thousand times better. I would disregard entirely any reviewer who uses weight as a factor in evaluating PSU quality.
sprockkets - Friday, October 29, 2010 - link
If it is such a poor test, why not then compare the weight and find out?It isn't as poor as you want it to be for arguments sake.
Phaedrus2129 - Friday, October 29, 2010 - link
Then all the PSUs with passive power factor correction would be hailed the best because of the weight added by the massive PFC coil. Vs. APFC units with lighter, but more effective components (couple switching transistors, a small coil, shares the primary capacitor, and a controller IC, still weighs less than a PPFC coil).sprockkets - Friday, October 29, 2010 - link
Bud, it's just a simple metric. Like you know, how a standard InWin PowerMan 350w PS weighs 2 lbs 10 oz and a standard FSP 300w power supply weights 3 lbs 5 oz.Besides, I wouldn't compare a passive vs. active PFC power supply anyhow and make that mistake.
Phaedrus2129 - Saturday, October 30, 2010 - link
I can see just recording the weight for posterity's sake, but one should *not* use weight as a metric of quality or performance. All more weight indicates is more components, heavier heatsinks, thicker wiring, heavier housing. For making a split-second field judgment, sure, but it is made completely redundant by opening the power supply up to appraise components and quality.I can tell far more about a PSU's quality from a quick glance at the secondary-side rectifiers than from measuring its weight.
Stuka87 - Friday, October 29, 2010 - link
I really liked seeing the comparison of the three. I would have liked to of seen a 4th super high end PSu thrown in, but it may have been a bit redundant.As for the low end, there are certainly better supplies out there for that price. You can even get lower end Antec's (like the 430 Basiq) for the same price as the one that blew up and while its not as good as the better Antec's, its better than the chinese no-name stuff.
benedict - Friday, October 29, 2010 - link
The review is clearly biased towards the higher-end PSUs. I don't dare say the reviewer deliberately picked a very poor part just to prove his point. There are some very decent PSUs for 30-40 euro that don't blow up at 50% load. For example, the FSP Saga II achieves 80%+ efficiency, costs about 40 euro and is very silent. Please, show some real part in the value price section and not some handpicked garbage.Phaedrus2129 - Friday, October 29, 2010 - link
This unit is actually above average for "garbage" power supplies. If he were intentionally picking a terrible PSU he'd choose something from Leadman, or Sunpro, that will blow up at 250W and have ripple in the 300mV+ range on all rails.marvdmartian - Friday, October 29, 2010 - link
In almost 10 years now of building my own systems, I have only ever been 'stung' by 2 power supplies. Both of them were Antecs, which died long before they should have, and both of them took out a motherboard while they were at it.Needless to say, I'm somewhat reluctant to ever trust an Antec psu to power my systems. Fool me twice, shame on me......fool me 3 times? I don't think so!!
OCZ would get my vote in this competition, hands down.
mmatis - Friday, October 29, 2010 - link
Especially since NewEgg is offering it with a $15 MIR through 31 October. It has 433 reviews on their site and gets 5 eggs.