Well I got a PC with these specifications and it lags bad. Best times I only get 15 FPS. :O
AMD Athlon 64 X2 Dual Core 6000+ with 3,22Ghz
6GB DDRII-RAM800 Dual Channel
NVIDIA GTX650Ti with 2GB GDDR5-RAM 128bit and CUDA
Windows 7 Home Premium 64bit
I guess it's the programm itself or it needs a quad core processor.
I also tried to overclock the CPU and the GPU and it was still the same.