Well i have a AMD 955, 8gb of ram and two WD 640gb on raid 0 that tops on 200mb/s of read/write. My cpu playing FFXIV is around 50% load and the GPU goes from 30% (outside ul'dah) to 90% (on ul'dah).

I tested and i tryed chaging a lot of configuration and nothing change the fact that i have 30fps~ on ul'dah. I test my new GPU with a few others games (MW3 and AC:L) and they run flawlessly with all settings maxed (even AA @ x8).