I'm usually getting around 90 fps, on my crafts with lots of kerbals (20+) using deepfreeze. The second the GUI opens though my framerate immediately drops to 20. It goes back to normal once I close the GUI. This is on ANY craft that has a deepfreeze module & a large amount of kerbals in them.
Running KSP 1.12.5 on Windows 10 64bit
System Specs:
RTX 4070 Super
AMD Ryzen 9800x3D
32 GB DDR5 6000Mhz CL30 Ram