Performance issue on Windows 8.1


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.

System specs:
MSI GTX 750 ti oc
Asus Z87-A
core i5-4570
8GB mem

So my question is, is it normal that cuda is slower on windows 8.1?


The kernel launch overhead etc. due to the graphics driver (WDDM, see might be higher on Windows 8 than in Windows 7.

Please file bugs for all significant performance regressions, using the bug reporting form linked from the registered developer website. Thank you for your help.

Thanks for your responses.

Hannes, there is a typo in you link. I red the blog post and when I have some spare time I will try the compute-only driver.

njuffa, I registered and am waiting for approval.

One other thing I tested is running 3dmark dx11 tests. These are the results of the Icestorm test.
Windows 7: 143822
Windows 8.1: 138586

So I think it is not a cuda related issue but more a general driver related issue.

Approval of registered developer applications normally takes one business day. Since we have a holiday weekend in the US, the next business day is Tuesday May 27. I am guessing, based on your user name, that you may be located in Europe, in which case you may have to wait until Wednesday due to time zone differences.

I briefly checked with the CUDA driver team, and they were not immediately aware of any performance issues with Windows 8.1 versus Windows 7 and suggested filing a bug. I assume your experiment was a tightly controlled one, that is, besides switching the OS, all the hardware and software components remained the same?

Yes, I am living in the Netherlands.
The two tests were indeed done on exactly the same hardware.