@tilleroftheearth thanks for running those tests It really does seem to be an "it depends" scenario a lot of the time, especially when used on programs that are used daily. For games, it seems more clear cut - it either works fine, or it doesn't. FCU seems to have a few issues around system lagging after a couple of hours of use, but it can't be that since your speed went right back to normal after uncompressing You say you used an i7 QC - what exactly is it if you don't mind me asking? It really is tough to call it one way or the other. It does that because I intentionally designed it that way so that users don't accidentally go compacting boot files - bad things happen if you compact those.