Oblivion will not work.
I've reinstalled, updated all my drivers, set it to a single core program, tricked it into using the correct shaders, and disabled all mods.
No matter what, it refuses to run above 20fps, on any setting.
My computer is relatively beast. a Phenom II 720 BE 2.8, overclocked to 3.4 with the 4th core unlocked, 1600mhz RAM, ATI Radeon HD 5870, etc.
I've seen a lot of people talk about how Oblivion runs at 20fps on powerful systems, but all the fixes haven't worked for me.
Any ideas?

Do you get framerate issues everywhere?? Or only when looking at the IC for example, or in the IC Waterfront??

What background processes are running while you try and play?