you should try CPU mining Cryptonight I bet you would get more H/s with that CPU than with your GPU.

When I mine Cryptonight coins I use a GPU miner and a CPU miner at the same time because my CPU almost gets the same amount of hashes as my GPU.
Also I can recomend https://github.com/fireice-uk/xmr-stak-cpu and https://github.com/fireice-uk/xmr-stak-nvidia.