Christian,
A while back I posted a question regarding performance gains to ccminer versions newer than the v1.0 that I was using. Recently I had to reload my computer from scratch (Xubuntu 14.04) so I compiled v1.2 with Cuda 6.5, driver 340.29. Whereas with two GT640 (GDDR5) mining BTQ I was getting ~1.6Mh/s combined, I'm now getting ~2.1Mh/s. 31% boost for zero added hardware. There will be a little something from me in your stocking soon. Thanks a bunch!

Z