Process Enhancer

Process Enhancer is a tiny tool that allows you to choose a program that is currently running on your computer and make your system focus on it. 

WARNING. To prevent counterproductive results do not ask your system to give a higher priority to more than two processes or applications. If you don't follow this warning, using the tool could be risky.

You can group related processes, change the level of priority to be set, or change the language of the app in the Options menu.

SingleProcessEnhancer (SPE) is a tiny console version, that works with process group names. It is a lot faster than Process Enhancer, if you don't mind the UI.