Prices and Conclusion

All the power supplies seen today perform well under normal conditions, though Amacrox showed us why we actually test under stress conditions like the heat chamber. This is in fact the first broken power supply we've encountered since we started reviewing PSUs this year; frankly, we're surprised it took this long. The cause of the failure is most likely a broken Schottky diode, but our investigation is ongoing.

Though the power supplies have different max outputs, they can be regarded as one group serving the high-end market. These are power supplies for people running more than one graphics card and multi-core CPUs, probably with some moderate overclocking as well. After looking at the test results, we like the Cooler Master M850 and Antec TruePower Quattro 850 the most. They are reliable and have very stable DC outputs. They also generate the highest efficiency scores of the group with up to 87% at a medium load of 400W (with 230VAC). However, the ripple results could be better, and from in terms of noise the Cooler Master performs better than the Antec unit.

At the end of the day, it often comes down to price - perhaps the most important factor for many buyers. While a PSU may perform incredibly well, if the price is too high many will opt for a cheaper competitor. We'll look at prices in both $USD and EUR.

Price Comparison


Some of the units are currently not available in the US, so we'll omit them from the $USD comparison. The Seasonic X900 is a very nice power supply, but we have to recommend looking at other previously tested models. You are far better off with the PC Power & Cooling Silencer 750 QUAD for a lower price and equal or better performance. Silverstone's Olympia is also too expensive right now, and given the performance in our tests we cannot give it a recommendation.

We mentioned Cooler Master and Antec already, as both generated good results. The price difference is quite large, and even though the Cooler Master performed slightly better we recommend the Antec TruePower Quattro since it's available for 140 EUR and $170 USD. At around 145 EUR or $200 USD the OCZ ModXStream places in the middle of the group, but despite reasonable performance we can't see much reason to buy an OCZ as opposed to the less expensive Antec TruePower Quattro.

Hiper targets the low to medium price regions. All of the units turned in a good performance today, and for the price we can certainly recommend them. Just pay attention to the available connectors, as we saw some important differences there.

Given the fact that the EUR to $USD exchange rate is quite high at the moment, all of the power supplies look like quite a bargain in the US. If you'd like to read more details of the individual power supplies, the remaining pages will provide pictures of the internals and additional commentary.

Product Comparison - Acoustics Amacrox Freestyle 750W
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  • engman - Wednesday, January 23, 2008 - link

    Can you explain beter the Voltage Ripple and Noise graphs?
    I really cant get it! Where is the graph scale?
  • engman - Wednesday, January 23, 2008 - link

    I was trying to find a good PSU and found this review.

    When you say: "The actual Power Supply Design Guide specifies that each +12V rail should not have any ripple over 120mV and the +3.3V and +5V rails should not have any ripple over ~50mV."

    Means that each power rail should not go outside this interval:
    11.88V < 12V < 12.12V 120mV
    3.25V < 3.30V < 3.35V 50mV
    4.95V < 5V < 5.05V 50mV
    Correct?

    How can 12.17V fall inside the specified range? "The 12V rails of the OCZ ModXStream tended to be high, but this is still acceptable as they fall inside the specified range."

    4.75V is inside the specs? and 5.13?
    "The 5V rails also remain within specs, but the last two units (OCZ and Amacrox) are very close to the lower boundary at 100% load."

    So what are the exac boundaries, or the voltage interval for each power rail?

    thanks
  • yelnatsch517 - Thursday, December 6, 2007 - link

    I noticed the Cooler Master reviewed was the M850 ESBA modular version of the RS 850 EMBA. Seeing as how it is impossible to find that model in the US, I am wondering if the model reviewed was either a EU version or a new model Cooler Master is planning on introducing in the near future and also whether the internals of the US EMBA 850watt version are the same.
  • jonnyGURU - Friday, December 14, 2007 - link

    The Cooler Masters are identical. Cooler Master refrains from selling the modular version in the U.S. due to Ultra's patent on the modular interface and threats to sue. You CAN buy the Cooler Master modular here in the U.S. if you get it bundled with a case. I've seen it pre-installed in some Stacker units over at Newegg.
  • stolennomenclature - Tuesday, December 4, 2007 - link

    I know im getting old and the old brain isnt what it used to be, but did'nt i read somewhere about dwindling oil reserves, skyrocketing oil prices, depletion of the ozone layer, and the need to reduce energy counsumption and be the green movement? I even thought I saw a trend with cpu makers trying to lower energy counsmption of their cpu's.

    You would'nt think any of this stuff was real when you see the trend towards bigger fuel guzzling SUV's and now a article like this - why on earth do we need kilowatt power supplies for a PC!

    If I was in government id have these things banned or else slap an enormous tax on them.

    People need to wake up and smell the roses. Its obscene that a PC should need a power supply over 300 watts. Even thats extravagant.
  • jonnyGURU - Friday, December 14, 2007 - link

    A PSU only puts out what's asked of it. So if you're PC only uses 300W, the PSU only puts out 300W. Really the only drawback here is that larger units typically cost more to buy, and neither you nor I are in the position to tell someone how to spend their money. ;)
  • ShadowStryder - Monday, November 26, 2007 - link

    Persoanally I like the new review layout.
  • Toadster - Saturday, November 24, 2007 - link

    850W of goodness for under $190
    http://www.newegg.com/Product/Product.aspx?Item=N8...">http://www.newegg.com/Product/Product.a...=N82E168...

    recently was on sale for $119 A/R
  • HexiumVII - Friday, November 23, 2007 - link

    Who manufactures the Antec 750?
  • Christoph Katzer - Saturday, November 24, 2007 - link

    The 850? Enhance.

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