ok little update on this.
I just installed a corsair water cooler unit. And did a slight overclock just to test, only upping it 0.2Ghz.
Launched FAF, re-ran cpu bench mark and still showing as 450 rating.
Am running HWMonitor on my second screen and the Clocks are showing correct all times 3492MHz on all 4 cores.
So alt tabbed and set my CPU affinity to cores 3 & 4 only, re-run bench mark and now got a 210 rating
So it would seem it's something to do with quad core CPU?
THought I would reply back in case anyone else is having same issue.