2 x GTX260, core i7-920, 12GB RAM, Win7 x64, nVidia driver v275.33, BOINC v6.12.26 (x64). Problem: unpredictably and intermittantly, GPU computation stops and the rig becomes unstable until I restart Windows or suspend GPU computation. I've tried testing the video cards, coming back with normal results. I've also reinstalled Win7 multiple times to no avail, the issue seems to crop up after a few days on a new install. My velociraptor (HD) makes noise while GPUGrid is running, so I can tell when computation stops. Also, the mouse becomes very slow and almost impossible to operate. I'm using a MS optical mouse.

I have got the unusable GTX260 for GPUGRID (65nm), but having the same problems with it as you have (Win 7 64bit, 8GB RAM, X6 1090T). Folding - unable to adjust the GPU load, very long system response etc... A had to turn back to 260.99 drivers. Maybe any GTX260 issue, I thought that it is problem of 65nm GTX260 only.

I own the core 216 55nm versions of the board.

I tried setting my hyperthreaded 4 core to 4 threads, because I'm running AQUA on the CPU. I think AQUA requires symmetrical multiprocessing. Set the CPU percentage to 50. Everything's fine - for now. Time will tell.

I have had same problem going on 45 days now.

It is not just a GPUgrid problem, but will happen on most any gpu project using cuda and a computer running dual cards, haven't seen problem on ati card but then i only have a sngle one in any system.

It appears only though to affect computers with twin cuda gpu's and as best i can tell this happens when switching apps, the new app loaded runs at 0%. Although i have not fully investigated this to be sure due to lack of time.

It also happens on different boinc versions, used 6.10.58 and 6.12.26 and had same problem on affected systems. NVIDIA driver upgrades also had no affect so far on problem.

I haven't seen problem on any of my single gpu systems, although all of those are 8800GT GPU's

I've had problem on two differnet systems both with twin GTX570's

Usually suspending the zero running app, will cause boinc to load a new gpu app and it runs fine, although the problem can reoccur next time, maybe, maybe not, an app switch occurs.