Unlock the other core if you can. One of my all Tahiti rigs uses the same CPU, and it was a real slowpoke with this miner until I realized it was the CPU holding it back and I hadn't unlocked both cores yet. That machine is now mining much faster.
Not a problem on my Intel rigs, though the 7 card rig isn't mining to its full potential yet. I suspect that one could use more CPU as well - it's a mixed Tahiti/Hawaii/Pitcairn rig. Incidentally, that one is more stable with 0.4.2 than 0.5. 0.5 will mine for a minute or two and then the cards drop out one by one.