Overwolf can be heavily affected by your screen resolution and display settings, if you set a high DPI desktop settings or duplicate your monitors it can cause your Overwolf dock and apps to work slower or even stutter.

Make sure that your DPI settings is not higher than 200% DPI (check out this guide) and if you are using more than one monitor choose the "Extend these displays" and not "Duplicate these displays" option (see image below)