Dual-GPU system is very slow: driver problem?

Dear comrades,

I have an i7 @ 3,7GHz and dual gtx-580, but only one is used to the computation. The OS is archlinux, CUDA is the newest, 4.2, gcc is 4.6. 294.40 is the driver.

My second computer is a E6600 @2,4Ghz, GTS 450. Cuda 4.1, gcc 4.4. 295.20.

The issue is: the same code is running faster in my humble computer. The time is 1 second. In my good computer, the time is 1,434 seconds. Even if a compile the code on the humble one and send to the good one, the time is the same.

The second issue: the kernel is four times faster in the good one, but the CPU time is 7x longer in the good one. In march this code used to return me 0,6 seconds. What should it be? A driver problem? Dual-gpu issue?


Tiago Carneiro

At least update drivers to the latest version 295.41, and both to GCC4.6, then benchmark again. Anything else would be subject to speculation.

Or downgrade the newer gcc to 4.4, so you use a version supported by CUDA.

unfortunately there is no 295.41 in archlinux repository.

And I tried to install gcc 4.4 using yourt, but with no success.