Throughout my playtime with Kerbal Space Program I have experienced the in-game frame limiter to be very 'iffy' when it comes to actually limiting the frame rate to the point that even when turning it down to 60fps using the in-game setting, it doesn't actually make any difference and I still experience well over 100+fps in some scenes and my GPU gets incredibly hot and the fans spin like crazy at full tilt.  To this extent I used to use KerboKatz's FPSLimiter mod:  Which works amazin