Welcome to AT, OP!
Hard to say, the Athlon II X4 is missing the L3 cache, so it does take a hit compared to the better Phenom II X4.
One thing though, that P965 mobo is ancient, that is the oldest chipset that can run Q6000s, and 3ghz is probably the ceiling. A Q6600 on a P45, it would be no contest, as I'd take the 8mb L2 Q6600 @ 3.2ghz well above a 3.4Ghz Athlon X4.
If you have them both (and own them), I'd honestly sell them both + whatever ram/parts you have lying around, and get a 955BE or i5 system built. Put together, you should easily be able to raise that amount of $ from both of those setups.