2D graphics slowdown with -686 kernels

[Michael V. De Palatis]

Hi all,

I recently noticed that the 2D graphics performance on my
Centrino-based laptop were lagging (coincidentally, the fglrx-enabled
3D accelerated graphics had no issues whatsoever), in addition to high
idle CPU usage. For example, the fading in xscreensaver took an
incredibly long time compared to how long it should take, and the
default firefox "busy" icon (the thing in the upper right, or in the
tabs in place of a page's icon when a page is loading) would animate
in a noticeably choppy fashion.

Anyway, I found a forum post about this same issue (link at the
bottom), in which the OP found that when using the -386 kernel
instead, the issue was solved. I tried this out, and sure enough, it
worked (additionally, I noticed the boot time was much faster, too).

I don't recall this being an issue long ago when I practically
immediately switched from -386 to -686 (originally with Hoary), and
unfortunately, I don't know when exactly this started. That said, does
anyone have any idea as to what this bug is related to?

I am currently looking through the buglist on launchpad to see if this
has already been filed, and if not, I will submit one. I just wanted
to see if anyone here had any clues to point me in the right direction
of the problem.

Thanks,

Mike


(Forum link)
http://ubuntuforums.org/showthread.php?t=205690&highlight=xscreensaver+slow