I was attempting to run my laptop at a lower resolution than the laptop panel. However, by default the video is scaled to fill the panel. This causes the image to be distorted (fonts look bad, etc).
On Linux (with Xorg, anyway), this behaviour can be tweaked with xrandr:
$ xrandr --output LVDS1 --set "scaling mode" "Center"
This is not a persistent setting, which is fine for my purposes.
Thanks to the Arch Linux Wiki article on Intel Graphics for documenting this.