My installation of Iceweasel is extremely sluggish in Debian Squeeze. CPU usage by
/usr/bin/Xorg seems to spike when doing very simple things like switching empty tabs, opening new tabs, scrolling. These simple tasks take up to two seconds to accomplish. The hardware is new and fast. The problem still exists in safe mode with no extensions enabled.
I read somewhere that if I set the
MOZ_GLX_IGNORE_BLACKLIST environment variable to true that it might help this type of problem but it doesn't seem to help the problem.