I have in my posession three i7 motherboards and 2 i7 920 chips. The motherboards are as follows:
Asus P6T Deluxe
eVGA X58
Gigabyte UD5
Unfortunately, there are issues with all three card types:
Asus P6T: At overclock speed (192 BCLK), this motherboard will not go into S3 sleep mode in Vista 64. The TurboV software will not allow the BLCK speed to be dropped to a sleepable speed (160 or so) from within Windows.
eVGA X58 : This board will not sleep at overclock speed but will decrease to 165 bus speed via E-Leet software. The problem is that the overclocking in E-Leet is corrupted any time the motherboard comes out of sleep mode.
Gigabyte UD5: This motherboard will S3 sleep at overclock speeds and will also lower to 165 BCLK speed via software. The problem with this motherboard is that the speedstep setup is not keeping 21 multiplier within MSFS X. I see multiplier jumping between 17 and 21 while FSX is working at less-than-optimal performance.
All 3 motherboards overclock both chips to 4GHz. The Asus board runs MSFS X as smooth as can be at 1280x1024 res with an ATI 4850 video card. Getting that same smoothness on the eVGA and Gigabyte boards has been a bit of a challenge so far.
Nehalem users... please share the experiences with your motherboards.