I am getting a Sapphire or XFX 5770 really soon. I have a Intel e5200 running at 2.93ghz.
I will OC it to about 3.2 when i get my new cooler.
Is it a bottleneck at the moment for upcoming games like MAFIA 2?
Provided the games you can play are not multi-threaded and CPU intensive (ie, Microsoft flight simulator X) you will be fine. Basically, most games the CPU will not be the bottleneck.