Harpertowns do not have hyperthreading. 8x24=192 hrs minus a little from disk writing and switching wu's. But almost 50% time loss is unacceptable and wasteful. I did have the disks to spin down when possible but shouldn't have ate that much time. 8gb ram so that's not an issue. SATA hard drive so no issues there. I switched back to clean water and my crunching time is back to normal. Would have to suggest it's the project with issues.

Disk spin down is not a good idea when crunching. Advise to switch that power saving feature off.

I did. Still think its the project and possibly ubuntu. Its not doing tbe same thing on clean water project.

That could possibly be a mismatch between the older CUDA runtime library used by the GPU BOINC projects and the new driver.

Something like that happened to me a few months ago when I installed a new Nvidia driver and Collatz stopped running on my machine. Collatz doesn't provide the CUDA runtime library for Linux, so the user has to compile and install it herself. Therefore in that case, it was easy for me to just recompile the runtime against the new driver, and Collatz was up and running again.

I haven't installed new Nvidia drivers since I started running GPUgrid, so I don't know whether I"ll have problems with that project after updating drivers. I assume GPUgrid supplies the CUDA runtime, because I didn't have to provide it myself to run GPUgrid. So I can easily see how installing a newer driver could cause a mismatch with an older runtime supplied by them.

You're saying now that you don't have these big differentials anymore?