Maximum Useful GPU for Amd Athlon 2 x4 645 3.1ghz

[jd81]

My cpu is a Amd Athlon 2 x4 645 3.1ghz. I have 8 gigs of ram, currently I have an Asus Gtx 550 GPU. How much performance increase in higher end games would I see with a new GPU? What is the maximum GPU that makes sense to get as the CPU will be a bottleneck I assume at a certain point...

Thanks!

 

[clutchc]

I had that same processor in a budget build I did recently. I had both a 1GB GTX 560 OC and a 2GB GTX 650 ti OC cards in the system at different times. They were about equal in performance and played most games at high settings @ 1920x1080. The old 4 core Athlon II 640 is gaining new respect since more of today's games are quad core capable now. I wouldn't be afraid of using an HD 7850 or GTX 650ti Boost with it.
http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-2.html