Do I have any drawbacks running 1 GPUGrid WU and 4 CPU tasks (intel i5) at the same time?

Wouldnt setting the the core usage to 75% result in the same? Only that 1 GPU and 3 CPU tasks run + 1 idle core?

Or do I have to make changes to my app_config.xml?

Ok. Thanks very much.

I just tried out a new GTX 970 to answer that very question, and saw only a minor difference, though it will depend on your CPU, etc. In my case, I have an i5-3550, which has four real cores running CPDN work units, and I did not initially reserve a core for the GPU.

It ran the e2s105_e1s274f90-NOELIA_ETQunboundx1-1-2-RND6708_0 work unit in 4 hours 11 minutes 10 seconds.

Then I reserved a core, and it ran e5s56_e1s534f55-NOELIA_ETQunboundx2-0-2-RND1360_0 in 04 hours 05 minutes 49 seconds.

I ran only one work unit in each case, so it is not much of a sample, but I think the differences look rather small. (Win7 64-bit, 352.86 drivers).

Undoubtedly correct, but my main takeaway is that the GTX 970, though very good, is not quite as great as the GTX 750 Ti for efficiency. But I am spoiled by the latter, so I think I will add a couple more of them to GPUGrid, and use the GTX 970 for Folding, where its extra speed is rewarded by the quick-return bonus. It all follows along pretty well to the performance results you gave earlier (https://www.gpugrid.net/forum_thread.php?id=1150&nowrap=true#41294), so it is not really a surprise.

... and use the GTX 970 for Folding, where its extra speed is rewarded by the quick-return bonus.

I am well aware of the 24 hour bonus, and the GTX 750 Tis can do it. The work units might get longer, but also GPUGrid might come up with improved software. And the new Noelia ETQunboundx show that they might go down again too. Moving cards around is just part of the process, and the GTX 750 Tis are the most efficient for any project I have used them on, so they will find a home somewhere.

I didnt want to open a new thread. Another question.

How do I limit the interval in which WUs are sent. If I get 2 gerards in a row, the second one has a high propability of not getting done in 24 hours and Id like to avoid that.

Also. Has someone figured out what the best clocks for a 970 are when underclocking to get best performance per Watt?

If you don't want work to be cached, then set your cache settings to not get it!

Open BOINC Manager, find the "Computing preferences...", and look for the following 2 settings:
- Store at least x days of work
- Store up to an additional y days of work

(x + y) is, essentially, the maximum that BOINC tries to cache for a resource.
You are in control, and if you want, you can set both to 0, for maximum bonus credits, I believe.