I have set AppleAntiAliasingThreshold on my computer as you can see: $ defaults read org.gnu.Emacs {     AppleAntiAliasingThreshold = 14;     ... I then start Emacs pretest 24.3.91. I see antialiased fonts which is incorrect  behavior. My 24.3.1 Emacs shows the default font face as non antialiased,  as the font size is under the aliasing threshold size. Here's a side by side screenshot. Left one is correct, right one is not: http://i.imgur.com/7ypo5Vw.png I'm running both emacs versions on the same computer, so config should be the same. In GNU Emacs 24.3.91.1 (x86_64-apple-darwin, NS apple-appkit-1038.36)  of 2014-05-12 on bob.porkrind.org Windowing system distributor `Apple', version 10.3.1265 Configured using:  `configure --host=x86_64-apple-darwin --build=i686-apple-darwin  --with-ns' Important settings:   locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect:   highlight-parentheses-mode: t   yas-global-mode: t   yas-minor-mode: t   diff-auto-refine-mode: t   nxhtml-menu-mode: t   winner-mode: t   ido-ubiquitous-mode: t   ido-everywhere: t   gud-tooltip-mode: t   delete-selection-mode: t   tooltip-mode: t   electric-indent-mode: t   mouse-wheel-mode: t   menu-bar-mode: t   file-name-shadow-mode: t   global-font-lock-mode: t   font-lock-mode: t   blink-cursor-mode: t   auto-composition-mode: t   auto-encryption-mode: t   auto-compression-mode: t   column-number-mode: t   line-number-mode: t   global-visual-line-mode: t   visual-line-mode: t   transient-mark-mode: t Recent input: M-w M-x v  e r s i o n   M-x r e p o r t   C-y SPC C-g C-a C-k C-g C-x C--  C-- C-x C-+ C-x C-0 M-x Recent messages: [yas] Loading for `text-mode', just-in-time: (yas--load-directory-1 /Users/myusername/.emacs.d/elpa/yasnippet-0.8.0/snippets/text-mode (quote text-mode) (quote nil))! [yas] Loading compiled snippets from /Users/myusername/.emacs.d/elpa/yasnippet-0.8.0/snippets/text-mode For information about GNU Emacs and the GNU system, type C-h C-a. 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