Does my Amd Athlon X2 5600+ 2.9Ghz overclock bottleneck wif my HD4850 IceQ 4 gpu??
and
How much the performance increase if I upgrade my current cpu to Amd Athlon II X2 270??
If you are going to upgrade and your system supports it, you might as well try to get a 4 core. Especially on an AMD rig, where CPU performance is weaker than Intel core for core. The "AMD Athlon II X4 650" is about the weakest performance I would recommend to anyone. It is comparable to the Core i3-2100 which is as low as I recommend for Intel CPU's.