The revision 7 BIOS adds ECC features (inc., off the top of my head, Chip Kill and various scrubbing options) - but I've found that Windows 7 will fail to resume from hibernation if 'MCE (Machine Check Exception) on ECC error' is enabled.
In fact often, an attempt to resume will result in the machine powering off completely, and showing no signs of life (other than the blue power lights on the board, which were lit) until the power is physically removed from the PSU for at least 30 seconds. The PSU is high-quality and works perfectly in a number of other systems, so this is almost certainly a motherboard problem rather than a PSU issue.
As with the other significant issues I've encountered with this board, I've reported the issue to Gigabyte technical support, who report that they've been unable to reproduce the problem.
