GIMP is free and it is great, but sometimes it can be slow as crap. And annoying.
Here's some things I've done and I can say right now it is not slow at all.
It's running like a smooth champ.
I don't know what the magic combination is,
but I have applied all these things to my GIMP as it is right now.
FIRST: Make sure you have installed 2.8.18 - more precisely, anything but 2.8.14!
2.8.14 has a file that is not the right version and so it is slow.
Second: Increase your tile cache size.
This is actually talked about in more detail on the GIMP.org site. First, 'search' your computer (under the start icon or the magnifying glass next to it on 10) for 'ram' and then 'view RAM info'. Take a note of how much usable RAM you have on your computer. Then go to GIMP and edit>preferences. The window that comes up will have a 'tile cache' option - this tells GIMP how much of you