About 20 years ago I used to play Unreal Tournament. There was a PVE mode and it was awesome. I'd play with a bunch of friends and that was our favourite mode. This reminds me of it A LOT. I am loving this game. I was getting tired of the same old zombie PVE.
You get more FPS but it's not worth it because the gains are so minimal. Plus the mobo has to be able to handle the higher speeds too, which they all can't do.
The only time I upgraded my CPU was when I went from an AMD Athlon XP 2000+ to a 3200+ Barton. Otherwise it was a new PC completely.
EDIT: NVM, I lied. E8400 to Q9550 also.