I was running cudaminer with execoin on an uptodate installation of Windows 7 with about 127khash/s.
Since I upgraded to Windows 8.1 I only get about 117 khash/s.
Both installations run the same driver (335.23) and the same cudaminer (2014-02-28 x64).
I tried the latest beta drivers (337.50 and 337.81) and also set my power saving settings to full speed, but none of that changed the speed. I also compiled the current cudaminer with cuda 6 and compute_50,sm_50 code generation. That was even slower.
MSI GTX 750 ti oc
So my question is, is it normal that cuda is slower on windows 8.1?