Scratch

I would check to make sure that you don't have a project running, because that puts a large load on the CPU, even if nothing is actually happening. Other than that, I'm not sure.

Well, I don't mean that you shouldn't have Scratch open. I mean that you should stop the project that you have open with the stop button when you don't need it running.

Never mind, I figured that (if you are running Scratch) you can right-click on the Scratch window button thingy in your taskbar (if you have Windows). Roll your mouse over to VM Preferences, then to System Configuration, and then click on Reduce CPU Usage. 

Greatdane wrote:

I remember there was a trick to raise Squeak maximum CPU usage or something similar. Maybe you could do the same, except lower it?

Then something bad might happen, though.

Yes, go to task manager and choose the processes tab at the top. Then find the Scratch.exe process and right click it. Choose set priority and lower the priority. This should help other applications run faster even with Scratch in the background. Just make sure you give Scratch normal priority again when you go back to using it 

Also, I think minimized windows use less CPU by default so try minimizing it instead of having it behind you active window if that is what you are doing.

The first method should work best 

If it still doesn't work, it could be something called "dumprep". All it does is take up CPU, so I usually end it. I've never heard of it on any computer except one:my family's.