Wow. My station has 607 parts and my MET clock is already constantly yellow. I still need a few parts up there - fuel tanks actually. But as you said, EVA and docking is still fine. The rendezvous pause is real. Especially annoying in time warp mode when the game stucks and then suddenly you are already behind your station and have to go another round...
My PC is i5-6500, 16GB RAM and a very old AMD R7 265. Maybe a stronger CPU would help