Quote from: cbuchner1 on February 04, 2014, 01:05:59 PM

Quote from: morbooo on February 04, 2014, 12:44:30 PM

Quote from: cbuchner1 on February 04, 2014, 11:54:19 AM

Quote from: morbooo on February 04, 2014, 11:50:24 AM

I'm having an issue mining scrypt with two GPU's: every time I start cudaMiner, one of them (not always the same) seems to return results which mostly doesn't validate. This is tested on Linux, using cudaMiner master, tested both on Z14x14 and T14x32. When I mine using a single card (selected with -d) all results validate... Any idea?

this is a long shot: Would it help to downgrade the video driver to the exact version hat shipped with the CUDA 5.5 toolkit download from nVidia? Of course if your video cards are newer than this driver release, this is a no-go, as the driver would not recognize them ;-/

I'm using the NVIDIA drivers from the Debian repositories, so downgrading isn't that easy... That said, I'm currently using the 319 driver series, which seems like the earliest one supported by CUDA 5.5. I've tried upgrading to the 331 driver series, but that doesn't change a thing.

I think your bug report is the one that made my mind go

The CUDA constant memory (the c_N loop trip count, etc...) of most CUDA kernels is only initialized properly for the first GPU (use of a single static variable to mark initialization instead of a thread-specific static variable). Which explains the majority of the crashes people are seeing with multi-GPU. Thank you. The Fermi owners use a kernel that doesn't yet make use of such constants, and hence the multi-GPU support is working fine for them.

So this is also on the FIXME list for tonight.

However I think that in your case where you run two cudaminer instances this cannot be the root cause. So we will have to keep looking.

Christian

Mate any idea why although
I have 2 GTX 780 (and two cuda miners) one shows 520 khps and the other 605? Can it be that the one that the monitor is plugged loses hash power because of it? Any idea what is going on?