Intel's Haswell processors are on the way, but it appears some power supplies may have some issues getting things started. A new report shows that Haswell's C6/C7 states require 0.05 amps on the 12V2 rail, which could be a problem as some PSUs can't supply that low level power. If that's the case then it opens up a lot of stability problems or the simple fact of having a PSU shut off entirely. Intel's Reseller Center website includes a handy list of power supplies, and when you sort by a minimum 12V2 load of zero amps, there's a grand total of 23 units that meet the requirement: 19 Corsair, three InWin, and one Seasonic. There could be more that support it that aren't included on Intel's list, but chances are it won't be too many more.
However, despite all of this there is still some good news. Corsair's Robert Pearce believes motherboard manufacturers could disable the C6/C7 states in the BIOS to ensure compatibility with more PSUs. Users can always enable those states later on once their power supply supports them. Corsair is working to make sure all of its PSUs support the C6/C7 states, and hopefully other companies do too.
Source: Tech Report