Your GPU(s) will be more fully utilized if you run more than one work unit per GPU.
We have discussions on several forums about writing an app_config.xml file to place inside the milkway project folder. Here is a discussion at EVGA that will give you an idea of the contents. I don't have Boinc on this computer, but I presume that you are on Windows. To begin, you need to go to Folder Options and unhide hidden files and folders. You will find a BOINC folder in If you want to run three work units per GPU, the value in
would be 0.3. The number entered for GPU and CPU usage must two digits, such as 1.0, 0.5, 0.3, etc.
Edit: I didn't finish my post and didn't know I had posted at all! As Nick Name said above, we need to know more about your computer.