CPU overvoltage resetting after sleep on Asus P8Z77
I've got a 3770k on an Asus P8Z77-M.
It works great, clocking up to 4.4 GHz with no problems with temperatures, running Win 8x64 very nicely.
But, there is a serious problem. After waking from sleep mode, the system is very unstable, crashing within a minute. I've traced this to the CPU core voltage. Normally, the BIOS provides a little overvoltage to the CPU, or this can be programmed manually. However, after waking from sleep mode, the CPU voltage reverts to stock, but the clock speeds remain overclocked.
I've been able to prove this at mild overclocks, and using monitoring/testing software, which proves the CPU voltage underload drops by about 0.15V after waking from sleep mode.
Is there any fix for this? Presumably, it would have to be in the BIOS, as the OS won't be able to do much for it.