The Haswell launch gets just a little more complicated each day, with the latest wrinkle being that standard ATX power supplies that conform to the ATX 2.3 standard may not actually be capable of supporting Haswell's extremely low power sleep states. The result has been power supply manufacturers scrambling to see if their power supplies can handle Haswell's requested 0.05A on the 12V rail as opposed to the ATX 2.3 minimum's 0.5A.

Both Corsair and Sea Sonic have been rigorously testing their power supplies to determine which ones definitely can handle Haswell's C6/C7 states, and both have a list of power supplies which are certified to run Haswell, and in the case of Corsair and their substantial portfolio, which power supplies should be able to handle Haswell with no problems.

Starting with Sea Sonic, the following power supplies are certified Haswell ready:

Series Wattages X Series 650, 750, 850, 1050, 1250 Platinum 660, 760, 860, 1000, 1200 Platinum Fanless 400, 460, 520 G Series 360, 450, 550, 650 M12 II Bronze EVO 750, 850

Corsair is a little bit more complicated. Certification testing is ongoing, but the following power supplies have been guaranteed to be fully compliant with Haswell:

Series Wattages AXi 760, 860, 1200 AX 650, 750, 760, 850, 860, 1200 HX 650, 750, 850, 1000, 1050 TX-M 650, 750, 850 TX 650, 750, 850 GS (V2) 600, 700, 800 CX 750, 750M

Corsair's validation efforts continue on the following models (predominately legacy), which they say are "likely compatible" but are not confirmed yet:

Series Wattages HX 520, 620 GS (V1) 500, 600, 700, 800 CX-M 430, 500, 600 CX 430, 500, 600 VX 450, 550 VS 350, 450, 550, 650

If you're looking to make the jump to Haswell next month, the best thing you can do is likely going to be to watch the homepage and support page of your vendor of choice. Haswell will still work just fine with most power supplies, but you may have to disable these lower power sleep states to maintain stability.