So I'm building a new workstation right now, and by no means is this the first time. The board is an ASUS P8P67, and the CPU is an Intel 2500k. I plan on running the OS off of a RAID0 array. I image my OS partition on a regular basis, so I'm not worried about being in RAID0. My question is this. I can either go with two WD 74 Gb VelociRaptors or two Segate 500 Gb drives. Normally this would be a no brainer, I'd go with the 10k drives. But the WD drives are ATA/300, while the Segate drives are ATA/600. How will these two drives compare in performance? Does SATA 3.0 have as much an impact as a SATA 2.0 drive running at 10k RPM's? This is a desktop workstation, I'm not concerned about gaming. Much more concerned with CAD and applications. Any thoughts?