Comment 17 for bug 12829

by default on i386 and powerpc, this is done if the monitor is capable.
experience has shown that the refresh rate used is typically 75Hz, maybe 70.
the only architecture where this does not hold true is amd64, where because of
certain limitations which are technically incredibly difficult to overcome, we
have a choice between pleasing the submitters of bugs like these, and making
peoples' monitors explode. personally, I think glass shards all through your
eyes and face is a little more harmful than 60Hz.