Kerbal Space Program

My save game was waiting for a window to transfer back from Duna (on a very important rescue Jeb mission!) At time of initial loading the game was using roughly 2.7Gb of RAM. After time warping over 1Y in-game time at 10,000X speed, bringing the speed back down to 1X caused my framerate to tank to ~2fps, whether in orbital map view or viewing the craft itself. Speeding up time again improved the framerate again, see video here: https://www.youtube.com/watch?v=8RewdrX_QZc

I saved, exited to main menu and continued the game from there, at which point I experienced this stuttering issue which I have noticed after 2h+ play sessions, video here: https://www.youtube.com/watch?v=vHurvg8Lo74

At this point I checked in task manager and the game was eating up 3.5Gb of RAM out of my 8Gb total, at this point it had been running for just over an hour. I exited the game again with the intention of restarting the program but it crashed on the way back to the main menu, please see attached crash.dmp and error.log for details on that particular crash.

System spec: i7 2600k, 8GB 1333mhz DDR3, twin AMD R9 280X, Windows 7.

Mods installed: FAR, MechJeb, B9, TAC fuel balancer, Part catalogue. (All most recent versions, compatible with 0.25.)