Can't answer most of your questions, but that power supply sound beefy enough to me. You might better post this question at tomshardware.com, rather than this graphics forum. Does the air coming out of your box feel very hot? Are your fans changing speed as the machine heats like they should? How is your Windows cache ("pagefile" or "swapfile")set up to use those new drives (assuming Windows XP)? Typically you would set that to use a non-boot drive at twice the size of your amount of memory (but you need at least a small pagefile on the boot drive as well, i believe). Always maintain at least 20% of drive space on the boot drive free for Windows itself to use.