I recently re-built emacs 23 from cvs and there's a noticeable delay in many repainting operations. Typing is sluggish and redrawing a buffer when switching to it is noticeably slow. So I tried to measure the difference. I started two versions of emacs with --no-init, loaded nothing, and immediately ran elp-instrument-function on "ibuffer". Here are the results: emacs(GNU Emacs 23.0.60.1 (i386-mingw-nt5.1.2600) of 2008-02-20 on U0103223-XPA) Function Name Call Count Elapsed Time Average Time ibuffer 1 0.0 0.0 GNU Emacs 23.0.60.1 (i386-mingw-nt5.1.2600) of 2008-05-12 on U0103223-XPA Function Name Call Count Elapsed Time Average Time ibuffer 1 0.032 0.032 I ran elp-instrument-function again and got: ibuffer 1 0.047 0.047 The time difference is very small, but with a loaded up emacs config the time becomes very noticeable. I built emacs on windows-xp using cygwin(-mno-cygwin however), ming32-make. Both versions of the build where 'configured' the same: Here's the 'report-emacs-bug' important stuff: In GNU Emacs 23.0.60.1 (i386-mingw-nt5.1.2600) of 2008-05-12 on U0103223-XPA Windowing system distributor `Microsoft Corp.', version 5.1.2600 configured using `configure --with-gcc (3.4) --cflags -I../../include -msse3 -O3' Important settings: value of $LC_ALL: nil value of $LC_COLLATE: nil value of $LC_CTYPE: nil value of $LC_MESSAGES: nil value of $LC_MONETARY: nil value of $LC_NUMERIC: nil value of $LC_TIME: nil value of $LANG: ENU value of $XMODIFIERS: nil locale-coding-system: cp1252 default-enable-multibyte-characters: t Major mode: Fundamental Minor modes in effect: tooltip-mode: t mouse-wheel-mode: t file-name-shadow-mode: t global-font-lock-mode: t blink-cursor-mode: t global-auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Recent input: M-x M-p i e l p 0 - i n s t r f u n i b u f f e r M-x l o a d - l i i b u f f e r M-x M-p M-p M-p M-x i b u f f e r q C-x b C-g C-x C-b q C-x 1 M-x i b u f f e r - e l p - r e s u l C-SPC M-w q M-x r e p o r Recent messages: goto-history-element: Beginning of history; no preceding item elp-instrument-function: ELP cannot profile autoloaded function: ibuffer Loading ibuffer...done Updating buffer list... Formats have changed, recompiling...done Mark set Updating buffer list...done Commands: m, u, t, RET, g, k, S, D, Q; q to quit; h for help Quit Mark set