1-)Dual GPU problem. You need to flash your motherboard to latest bios to make your Dual GPU cards (such as 4870x2 GTX295 9800Gx2) work.
3-) You have to set CPU voltage and VTT to same value, so your system will be stable, and cpu-z will read the actual voltage you put in the bios.
2. is it really unsafe to use it with Thuban? im considering an upgrade