Efficiency and PFC

230VAC, 50Hz
Load Efficiency PFC
10% 83% 0.800
20% 89% 0.903
50% 91% 0.970
80% 89% 0.982
100% 88% 0.986
110% 88% 0.989


115VAC, 60Hz
Load Efficiency PFC
10% 82% 0.917
20% 88% 0.970
50% 90% 0.986
80% 88% 0.990
100% 88% 0.993
110% 87% 0.994

With 80 Plus Gold certification, we expect high efficiency and the AX750 delivers. It doesn't matter whether you live in the USA or Europe; the efficiency is always high and 80 Plus Gold is no problem for the design. Maximum efficiency comes at 50% load as expected, but even on 115VAC the efficiency is always at 88% or higher provided the load is at least 150W. Worst-case efficiency at a low load of just 75W is still 82%, so we really can't complain--at such a low load, the difference between 82% and 90% efficiency amounts to only 8W. Besides, as we pointed out on the noise tests, the hardware required to even push a 750W PSU to the limits is such that you're likely to idle closer to 150W (or higher).

The power factor is also good,, staying above .90 on 230VAC as long as load is above 20%. That drops to just above 0.800 at 10% load, but any high-end system requiring the AX750 is going to be higher than that.

Voltage Regulation and Quality Conclusion


View All Comments

  • Chapbass - Tuesday, November 30, 2010 - link

    On the cables and connectors page: last para:

    The only potential issue is if you want to load up all we SATA connectors with a bottom-mounted PUS; the distance from the PSU to the first connector is only 45cm (give or take), with a fairly large 12-13cm gap between the connectors, so you'd want the HDD bays to be relatively close to the PSU rather than in the top portion of the case.

    First sentence has a few typos. Still reading, but figured I'd point it out.
  • Shadowmaster625 - Tuesday, November 30, 2010 - link

    Aren't all PUS's bottom mounted? Reply
  • Stuka87 - Tuesday, November 30, 2010 - link

    Many newer cases do use a bottom mounted CPU, but it is hardly the only form factor. Reply
  • Stuka87 - Tuesday, November 30, 2010 - link

    CPU should be PSU. Wish there was an edit :/ Reply
  • Iketh - Wednesday, December 1, 2010 - link

    pretty sure they're rear-mounted when bent over Reply
  • Nintendesert - Tuesday, November 30, 2010 - link

    Last page, first paragraph.

    "Gold requirements. 91% at 50% load is not to shabby."

    It should be "too shabby."
  • Chapbass - Tuesday, November 30, 2010 - link

    Gotta say this PSU looks impressive. I'm going to need something soon for my server (not much in the way of cpu and video power, but along the lines of 18-20 HDD's), and something like this might fit the bill. we'll have to see :)

    props to corsair, another solid unit.
  • prince34 - Tuesday, November 30, 2010 - link

    I've been looking for a new high quality PSU for a new build early next year. This looks very promising. Also, Newegg has a $20 mail in rebate and $15 promotional code with free shipping. Thats $135 up front and $115 in the end. That is hard to beat. Reply
  • mino - Tuesday, November 30, 2010 - link

    This left me puzzled though:

    "The AX has DC-to-DC for the smaller rails, so +12V feeds +3.3V/+5V and you can't use the whole 62A there."

    I know of exactly ZERO XXX-watt power supplies where you can load 3.3V or 5V _in_addition_to_ the XXX watts being consumed on 12V rails.

    Actually, most PSU's on the market do not allow anywhere near 99% of its rated load purely via 12V rails like this one. So if anything, such an arrangement should considered a plus.
  • Beenthere - Tuesday, November 30, 2010 - link

    These days there are lots of PSUs to chose from and the devil seems to be in the details. History has shown that Seasonic can produce good PSUs under their own brand and for other companies but that not all PSUs from them are not equal in design or performance.

    Without knowing exactly what the hardware differences are between PSUs and how this impacts performance or reliability makes it challenging when purchasing a new PSU. I watch hardware sites for patterns of issues with specific PSU models and brands when I'm looking for a new PSU.

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