Here you can configure the priority with which DOSBox runs.
Windows gives a program a certain priority. The higher this priority the more CPU time the program gets resulting in a speed boost. DOSBox is very CPU intensive so this will effect performance.
You can change two settings here:
1.
You can set the priority of DOSBox when it's active (when you're playing a game).
2.
You can set the priority of DOSBox when it's inactive.
That's pretty much all there is to it. If DOSBox gets unstable when you select a certain priority, lower DOS Box's priority a notch and see what happens.