Which hardware component affects blender the most in sculpting mode

I thing the Performance in sculpting mode is a little low on my System. When I’m sculpting at Level 8 the Orbiting gets noticeably slow, whereas sculpting performance remains quite acceptable. I have a quite Powerful 6 core Processor the AMD1090t which 3200 to 3600 Ghz 8 GB Ram and a Geforce GTS 250 and Windows 7 64. I know my graphicscard is getting a little bit old, could it be the bottleneck? If so what card doyou recommend? Or isn’t aculpting that Optimized in the current Builds anyway?