Totally fair, maker of cmux here. We fixed many RAM usage issues (latest version is 0.64.22), and also added an activity monitor to see how much RAM/CPU coding agents are taking.

My cmux has been running with 136 workspaces and 218 terminals, and has been hovering around 5.7 GB. Granted, the theoretical RAM minimum for this number of terminals is around 1-1.5 GB before real scrollback, so we definitely have more work to do.