Cold Test Results

For the testing of PSUs, we use high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox, and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs – 2014 Pipeline post.

The Corsair AX1500i delivered record-breaking performance at room temperature, with an impressive average conversion efficiency within the nominal load range (20% to 100%) of 94.9%. The maximum conversion efficiency is exactly 96.7% at 50% load, which is more than adequate for an 80 Plus Titanium certification under 230VAC input.

For 110VAC grids, the 80 Plus Titanium certification is more lenient, dictating an efficiency of at least 94% and thus the AX1500i should easily surpass it. Perhaps the most important point that we can make regarding the efficiency of the AX1500i is the low-load efficiency, which is at 85.6% at just 5% load, an astonishing figure considering that there are hardly any computer PSUs that will surpass 78% efficiency at 5% load. Of course, 5% load in this case is still 75W, and there are many PCs that idle at levels far below that value.

The cooling system of the Corsair AX1500i is based on "smart" thermal management, with the fan not turning on at all before it is necessary. Considering its output, the AX1500i is an astoundingly cool running unit, allowing it to operate without the help of the fan under loads that surpass the entire output of typical consumer/gaming PSUs. When the fan does start however, it does not remain quiet for long, with its speed increasing alongside the load. In the unlikely event that the AX1500i remains loaded at 80% capacity (or more) for several minutes, the fan is clearly audible from many meters away.

The Corsair AX1500i PSU Hot Test Results
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  • sweetca - Thursday, September 11, 2014 - link

    Thank you!
  • tim851 - Thursday, September 11, 2014 - link

    >>The advantage of having more power than you need is to let the components breathe better,
    >>widen the pipeline so to speak.
    What? This is audiophile-grade fluffy language. And a load of...

    >>You may not need 1500W, but the extra headroom provides for stabilty and overclocking potential.
    You either need 1500w or you don't.
    If you're overclocked setup draws 600w from the wall, having a 1500w PSU is not going to improve stability or overclocking.
  • quick brown fox - Thursday, September 11, 2014 - link

    Maybe he worded it with some level of ambiguity, but the point he wanted to come across can be easily understood.

    If your overclocked setup draws 600W from the wall, theoretically you can have a 600W PSU supply all of that without the PSU going out of regulation. However, if you still have some room for additional overclocking (from better cooling), your overclocked setup might draw an additional 50-100W, and your 600W PSU (depending on its quality) won't have that headroom to sustain the additional power draw, which would lead of course to instability.

    So what you're avoiding is the PSU becoming a bottleneck when you still have the capability to overclock further.
  • tim851 - Friday, September 12, 2014 - link

    Perhaps that's what he means.

    But the fluffy language he uses let's me rather suspect he's one of those people who believes a higher powered PSU makes his PC faster. Because moar power!!!

    Like the audiophiles who think a super-expensive HDMI cable that is thick as a child's arm is improving colors and clarity of their blu-rays.
  • DanNeely - Thursday, September 11, 2014 - link

    Maybe. If you've got a low power system with a decent smaller PSU this would probably be worse becuase you're in the sweet spot for the smaller PSU and in the low-load suck range on this monster. if you're running a 500W box on a 550W PSU, this would probably do better at full load since the 550 would be in the nearly maxxed out suck zone; OTOH the 550 would probably still do better at idle. You normally get peak efficiency around the 50% point and good performance from 20-80% before falling off at either end (see the curves on pages 3/4).

    80+ Platinum is the first 80+ spec to set an efficiency requirement at 10% too; and platinum units generally do a lot better at low loads. OTOH since they're all still halo priced; unless you live somewhere with really expensive electricity they're not going to pay for themselves vs more mainstream models.
  • AnnihilatorX - Friday, September 12, 2014 - link

    Different PSUs have different efficiency curves at different power loads, so it is hard to say. Generally they are most efficient between 20-80% load.
  • FriendlyUser - Thursday, September 11, 2014 - link

    Great product, but the price is only meant for high-end workstations and the like. I think it would be useful for such extreme products to enumerate the connectors.

    I am asking this because I was looking at the ASUS Z10PE workstation MB supporting dual Haswell Xeons with massive 150W TDPs. The MB in question requires 1xATX 24pin, 2x8pin EPS AND an optional but recommended 6pin EPS 12V connector for SLI/Crossfire. I haven't yet found a PSU with a 6-pin ATX 12V power connector, and I am almost certain it's not the same as PCIe.
  • vred - Thursday, September 11, 2014 - link

    It is the same as PCIE 6-pin connector. You have not found a PSU with a 6-pin ATX 12V connector, because there is no such connector. :)
  • vred - Thursday, September 11, 2014 - link

    Running this PSU to power my watercooled quad-Titan Black workstation running CUDA calculations. PSU remains surprisingly quiet and mildly warm to touch even under full load.
  • philosofa - Thursday, September 11, 2014 - link

    What a beautiful piece of hardware; fantastic to see something pushing so hard at the bounds that define 'well made'. Cheers for the review, was fantastic H/W pr0n to read :D

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