Otlecs,
70% Memory utilization is too high. Windows isn't reporting only physical memory usage, even though it leads you to believe it is. Page Faults are not the same as Page File Hits. (A Page Fault is a memory access error, its a completely different thing). When you have enough ram, and wow is not causing page file hits, it hardly uses any hard disk except when you are loading, or entering a new zone.
I was running 4 GB, with a 768MB Video card (so really only 3.25 GB) and it wasn't enough memory for me. I could tell because I couldn't run around Shatt without losing straggling clones due to freezing long enough to fall out of follow distance. Different disk setups had little to no impact. Adding 2gb of ram and upgrading to Vista 64bit enabled me to do loops around Shattrah full speed with no stragglers during primetime on friday night. Its night and day.