The WPF support multi-thread by default when multiply tiles, and we don't have the setting for multiple cores.
If you met the performance issue you can view this page for reference: http://wiki.thinkgeo.com/wiki/map_suite_performance_guide
And we have some suggestions for you:
Please group the layers you will won't get edit, put them in separate overlays and open cache for these overlays, the other layers can keep get edit.
You can simplify your data for each zoomlevel, render important features in higher level, and render detail features in deeper level.
The solution thinking is by reduce the render feature numbers to improve the performance.
Wish that's helpful.