For some time my Surface Pro 3 has been grinding when it really shouldn't. And a check of the Task Manager showed that a process called "System and Compressed Memory" was taking up an inordinate amount of processor time. Long story short, I found that this fix worked for me. If your Surface Pro or Surface Book is slowing down you might find it useful to take a look. I've no idea what the fix does (and nothing anywhere tells me) but it has made my machine much more responsive.