Phenom II 940 + GTX 480

I guess you're still fine at 3.0 GHz, yes your CPU will bottleneck GTX480, but not much...
Already have that setup? already try it?

I ordered it thursday, so it should all be in tomorrow. Here's a list of the (relevant) stuff in my rig:

GIGABYTE GA-MA770-UD3
Phenom II 940 BE (3.0 at stock)
Thermaltake Frio cpu cooler
4gb G.Skill Trident DDR2@ 1066
PNY GTX 480

Well... 3.0GHz won't be too much of a bottleneck, if you're very concerned about performance, then I reckon anything higher than 3.4 GHz, probably 3.5 GHz would 'stop' that bottleneck.