My bottleneck is well, a combination.
I forgot to mention, but i have SSD HDD aswell, for my OS and games, although it only uses SATA2 (due to my motherboard), and my motherboard also does not support newer sockets like the LGA2011 which i would really like,
this is the problem with building a PC and then upgrading parts - bottlenecks! .
When i first built my system i had my I7 920 and 2 x GTX260's and a non-SSD hdd, which by that time, was very fast .