Hi Thought I'd share my experiences from the last day in the hope it might save someone else some time in the future. I'm a dual booter with Ubuntu 14.04 and Win 7. I much prefer using Linux, but due to another game I'm playing I've been using Windows a lot recently and that's where I've been playing KSP also. I decided to try the 64 bit Linux client out to see if it was any more stable than the Win 64 bit (which IMO it is way more stable), however I was faced with a horrendous hit in performance ... pretty much made the game unplayable. Under 3 fps and a high physics load on a ship with less than 150 parts. Space centre, VAB & Tracking station all worked fine, the problem was only apparent when controlling a vessle or in map view. I know that the game runs fine in Linux on my machine as I'd run it before with no issues. Here's my specs : AMD Phenom 2 X6 1090T BE (OC to 3.8 Ghz) 8 Gb DDR3 1866 Mhz GTX580 3 Gb I thought that maybe with one of the recent updates something had gone wrong so I tried various fixes and settings alterations none of which helped the issue. Turns out that it was my copied (from Win 7) save causing the problems. Really wish I had of checked this earlier as I literally spent the whole day trying different settings, tweaks & mods to no avail. I'm pretty sure I've seen something similar to this mentioned in this thread (with regards to the settings.cfg?). Not sure, so many pages it's all a bit of a blur, however I would say that if you are migrating a save and are having performance problems this might be the cause. tl;dr Migrating saves across OS' can cause performance problems. Update: Looks like I jumped the gun on this one. The problem has just re-occured in my new (linux only) save, so something is causing this to happen. I'll update as I find out more. Update: It seems that Karbonite (or one of the mods packaged with it) was casuing the performance hit in Linux, updating it solved the problem.