OK, try changing the "suspend when non BOINC tasks active" from 75% - where it is now - to 0.
Then change the "on multi processor systems use __% of CPU" from -- where it is now - to 75%. On a quad core, that is like cutting 1 core from what BOINC will use for CPU projects. You can play with this number later to fine tune, but try this for now and see how your Moo! times change, ie they should drop like a rock again.