I forgot to tell you all what happened.
So the answer was in front of my face and I mentioned in this thread.
The CPU was constantly locked at 800mhz - hence the massive drops in performance.
The culprit was: Intel Thermal Monitor
Well, the actual culprit was my cooler was too tight on the CPU so it was tripping out the thermal monitor.
When this happens, it forces the cpu down to 800mhz.
I disabled it at first and then rejigged my CPU heatsink.
All fine now and in fact better than ever. Which makes a hell of a lot of sense now because I must have been having a minor performance hits thanks to the throttling.
Hope this thread helps to contribute to someone else sorting out their own PC in the future.