Told Nazaria about this tweak and the system improvement was 20FPS and thats not even on low render.
In rift folder right click and open in location the rift.cfg file.
Edit the line:
MainThreadCPU = 3
to
MainThreadCPU = 0
Basicly enables the cpu to use all the threads on the CPU.
Ergo, using more cpu power.
Give it ago!
Post your improvements under =)
Sorique