I've reached around cycle 500 in my world with decent fps with no stuttering whatsoever until today. After cycle 513 in my world my game's framerate drops and stutters more than it has ever had. I've had another world (before the release) that was 1500 cycles long and didn't lag so it's definitely not my computer being slow. I've gone back in auto saves but everytime it reaches around that cycle it lags a lot.
The one space ship I have came back around cycle 512 but it didn't lag after it landed. I have no idea what caused the fps drop.