It's finally working on my gtx 560, although it's an old card and only gets 95 kHash/s , is this ok ?
My CPU pulls over 600 kHash/sec, my oldish Radeon 5800 series pulls around 3000 kHash/s.
NVidia GPUs are way better at floating point math, AMD GPUs are way better at integer arithmetic which makes them better at hash algorithms.
I have same stats on cpu (I7 2600k 3.4Ghz)... Also heard that nvidia gpus are not good for this kind of work