Originally Posted by konst
Do what I did. Switch to ATI. There are some good deals for Radeon HD 5850 cards for around $260.
Other than that AaronP mentioned that Firefox may be slow cause it allocates larger pixmaps than the graphics card can handle. Maybe that's the same problem with KDE 4 cause KDE 3 isn't slow on Nvidia cards.
Thanks for your reply, And yes I'm really thinking to buy a Raedon HD 5xxx.
And, why does Firefox and KDE work just fine with Nouveau?