The TOTAL counts aren't comparable between use_gpu_fermat_test true/false, should look at 2-chains. I'll remove the TOTAL count in the next version.
Good to know, thanks! Looking at 2/3 chains then the gpu_fermat_test is faster by ~ 1.4x (I do have a weak CPU in there). Is the candidate difference a red herring (1/9 as many) or just the way it is reported?
I'm just not seeing stats anything like this.
With the fermat test done on the GPU I get...
0 fermats/s, 6.73269 gandalfs/s.
70.2502k TOTAL 1.79828k 2-chains 39.093 3-chains 39.093 4-chains
With the fermat done on the CPU I get ...
60338.8 fermats/s, 3523.21 gandalfs/s.
350.383M TOTAL 1.01852M 2-chains 64.7127k 3-chains 3.58685k 4-chains 298.904 5-chains
Ignoring the total, the fermat test on the GPU gives 1000x fewer 2-chains, and 100x fewer 4-chains. This is with 2 x 7950, a AMD FX(tm)-4130 Quad-Core Processor, and ubunutu 13.
Am I missing something somewhere?