I'm sure it would be playable.
Hell, my piece of junk laptop ran MW2 quite nicely(even though some maps were somewhat laggy). So it prolly won't run Black Ops anymore, but who knows. And CoD has quite stable and PC friendly engine.
I have:
2.0ghz AMD Athlon x2 64 QL-62
ATI Radeon HD3200
4GB RAM
So yes, you are safe.