Sean
Yes, that would be cool being able to switch off mem modules from within BIOS (or Windows, better yet). I don't think I have seen any mobo doing that, that would be Intel first I guess.
Can't remember right now but I believe we can save a profile in BIOS and use other settings, not sure though. Anyway, it's not exactly the same you want.
Don't know the voltage limits really but you must be close for sure. I believe someone (guess gtj) has already posted voltage limits for this board, not sure though.
Anyone tried populating all sockets with 2G sticks, for a grand total of 8G? Does it work? I believe the X38 chipset can only address 4G, correct?