How funny I was trying the same thing by going one by one on Compatibility
modes and it worked for me as well. It also works on Windows 95 "ComptMode" /
I don't know if its my computer but it certainly runs a little smoother when
under Windows 95, instead of Windows 98 / ME ComptMode. Also disabling
Desktop Composition might help it a little more.
If you wish to obtain better FPS and you already tried all that above, then
try to turn off the "Motion Blur" effect under your Video / Advanced
configurations; Try not to go under Antisotropic 4X cause the game just looks
bad. It is no use playing NFS:Carbon without max quality.
For the PC refs, here is my system:
64 3200+
2GB DDR
7900 GT 256MB
Hope it helps a little more. And if you find more ways to make it work
better please share and submit feedback to EA