Depends on your definition of lag. This is my rig.
http://valid.canardpc.com/show_oc.php?id=1757492
It's just as good, if not better than yours, yet I only experience the lag that comes with Alice regardless of how good your computer is—Camera turning being choppy, especially on small scale movements, being the primary example.
Also: You running anything in the background? Technically due to your use of HyperMemory, you're actually under the recommended memory requirement for Windows 7 (2GB untouched system RAM)