I found on Taris that when it started to get slow even with 6gb ram it was because it was using so much memory. It was having to grab from the hard drive. I could see the hard drive light going nuts exactly when my frames would drop. Just got to Corsair Force GT's and cannot wait to set them up. I know for sure that when it needs to hit the hard drive up for info it will effect performance WAY less than now with striped mechanical drives I have now
Thats why I went with the 16 RAM, I wanted the entire game to load into RAM so there would be as little paging as possible. But the irony is, the RAID 0 SSD's are as fast or even faster than my RAM so its totally seamless.