I keep a *slime-repl ccl* buffer visible in a separate frame so I can view the interpreter and my source code at the same time. As for recently, I noticed that scrolling in pretty much any buffer has become extremely sluggish: redisplays occur only rarely, with the result being that the text jumps around a lot rather than being scrolled smoothly line-by-line. When the *slime-repl ccl* buffer is not shown, this problem doesn't occur (and goes away). I use SLIME from CVS, 2009-01-09, in Aquamacs (based on GNU Emacs 22). I start up slime as follows: (require 'slime-autoloads) (slime-setup '(slime-fancy slime-asdf slime-banner)) (setq slime- complete-symbol*-fancy t) (setq slime-complete-symbol-function 'slime- fuzzy-complete-symbol) I tried setting the latter two variables to nil, to no avail. I tried `cancel-function-timers' on various SLIME specific functions in timer-idle-list, but they keep coming back. I also tried (setq post-command-hook '(ignore)) in the REPL buffer (and the buffer that I am scrolling) - it doesn't help much. I have turned off eldoc-mode in the REPL buffer, which didn't help much either. I'm running this on an up-to-date machine. If you can't reproduce, let me know what else I should check. Thanks - David