Comment 4 for bug 68404

I have the same problem, in particular [Alt]-[Tab] to suspend a mathematica window to the background takes about 4 seconds, even if the worksheet is completely empty.

The driver in the "device" section in my xorg.conf is "ati" (Radeon 7000/VE).

I have no trouble with any other kind of windows and also no trouble with Ubuntu 06.06.

Note that Mathematica comes with its own fonts which are installed automatically (which may be related to this problem).