I got the impression from a few short-term checks on one of my PCs that simply raising the priority of the graphics card feeder process (fahcore_21.exe or whatever it is called) from "lowest" to "normal" gets it back up to fair PPD even when there is 100 % other CPU load at "lowest" scheduling priority (e.g. a F@H CPU slot or a BOINC CPU project). Perhaps the below-normal/ second-to-lowest priority would already be sufficient too. I haven't checked this systematically yet, i.e. longer term, and compared to when any other CPU load is completely removed.



This is with Windows 7 (I also have Linux, but only with CPU clients), and recently I looked only at its effect on a small AMD GPU whose feeder process actually takes only very little CPU time. But if Windows 7 is tardy waking up that processes when it should be, then I figure that such scheduling latency would introduce stalls into the GPU workload.



On a related note, I have the option "Configure" -> "Advanced" -> "Folding Core Priority" -> "Slightly higher. Use this if other distributed computing applications are stopping Folding@home from running" enabled but it does not improve things. Apparently it raises priority of the fahcorewrapper, but definitely not of the GPU feeder process. Well, of course the problem here is not that the GPU client is not running at all, only that its throughput is decreased dramatically in presence of CPU load.



If my observation with manually raised priority was correct, then perhaps a feature request should be opened with Pande group for a third option which would raise the priority of GPU feeder processes. Or maybe it should not even be an option, but simply hardwired (schedule the GPU feeder at second-to-lowest priority, or even normal priority, instead of lowest priority).



I haven't checked at the folding@home support site yet whether something like this was already discussed there.