Frame Rate Drops in NFS Most Wanted PC

I upgraded my AMD Athlon II X4 640 3Ghz to a Intel i5 3470 3.7Ghz max. and now the stutterings and frame drops are gone.

edit: well, its "stuck" at 30 fps, even though i have lockto30=false

but it still feels like a completely different game. especially with fast cars like bugatti or koenigsegg

edit: it goes over 30 fps now and gpu usage is 98% now