i try 4 ssd ocz core raid 0 and maxi was around 600 MB/s reading
And thats your bottleneck.

Thats why I recomend this 32G system ram system (DDR2):

Wow folder in System Ram for $800


From what I read two video cards are more trouble then they are worth but as you say on X58 system once the data is in system ram you are good to go.