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With KMS enabled on Xubuntu 11.04, my virtual terminals are running at 60hz, the default for my monitor, while my X desktop is running at 75, the refresh rate I specified in my xorg.conf. How do I set the refresh rate/mode used by KMS so that it is something different from the default mode provided by my monitor?

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You can specify the resolution/refresh rate that the VT framebuffers will use on the kernel command line¹.

To do so, you want to add

video=<xres>x<yres>@<refresh>

to your kernel command line. So, for example

video=1024x768@75

would give you a 1024x768 framebuffer at 75Hz. The @<refresh> bit is optional.

You can edit your kernel command line on a one-time basis by hitting e from the grub menu, or to set it permanently you can edit /etc/default/grub, adding it to the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

like so:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=1024x768@75"

After editing /etc/default/grub you'll need to run sudo update-grub to propagate the configuration to your boot settings.

Documentation/fb/modedb.txt has the full specification of what options you can pass in to video= - if you have unusual requirements (interlaced, reduced-blanking, etc) see this documentation.

¹: This is due in part to the fact that there's no good way to notify VT users of resolution changes.

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    Notes to future readers as nooby as me: Add the video option to the GRUB_CMDLINE_LINUX_DEFAULT option, as such: GRUB_CMDLINE_LINUX_DEFAULT="video=1280x1024@75 quiet splash" Be sure to run update-grub.
    – raevol
    Commented May 27, 2011 at 9:34

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