I think that I may have solved the problem. It seemed to be the memory speed settings that I had set in the bios. Windows was flying along with them all turned up to full, but linux did not seem to like it at all. Since turning them down everything seems to have improved performance wise in Linux.
I wonder why windows can cope with and benefit from it but Redhat can't?
It's still a little slow though - perhaps more tweaking is needed. I checked the CPU thread thing and nothing looked too out of the ordinary. Which threads are worth prioritising to boost overall performance? (Or decreasing as the case may be)..
Thanks for your help btw. Steep learning curve here.