My rig is not the best, so I would imagine my CPU/memory are bottlenecks under certain circumstances. The build:
Antec 900 II ATX
Asus P5N-E SLI
Intel Q6600 at stock speeds (overclocking has not been friendly)
EVGA GTX 470 SC running latest x64 beta drivers
I used EVGA precision, GPU-Z, and Unigine Heaven to set and test a variety of overclock settings on this GPU
Congrats on the new card dude. The gtx 470 is a beast that nvidia handicapped with their not so good thermal design, noise, and power consumption. These cards love voltage and water cooling, if you decide to water cool it in the future you will be amazed. I have mine running @ 900/1800/2050...core/shader/memory. also i would recommend using MSI afterburner, its a great tool for ATI/Nvidia cards. I am thinking about buying another one soon but not sure yet.