I really do not know what is causing the problem of my desktop environment (D.E.) gradually slowing down. It seems to happen in Gnome 3.2, LXDE, XFCE, and KDE. I am running Ubuntu 11.10 and this problem started happening from a fresh install.
I have noticed that if I restart Gnome or otherwise re-log-in with any of the D.E.s the speed resets to normal. I don't seem to have and memory leaks that account for it and there are not any processes that are using excessive CPU cycles. Due to the symptoms I am guessing that there is an underlying package that interacts with all D.E.s that is the source of the problem.
Just to clarify, in extreme situations, if I let the slowdown continue without a restart of the D.E. my system will finally get to a point where everything, even my clock, freezes. The time over which Gnome slows down (noticeably after 17 hrs) is much less than LXDE, or XFCE but eventually they freeze as well. I didn't mention Unity since I haven't used it enough to verify the problem, but I don't see why it should be different.
Just in case this is relevant, I Suspend my computer rather than turn it off. I do this because of the greatly reduced load time and the 17 hrs I stated above is actual up-time, not time where the D.E. is actually active. However, the slow down does not seem to be affected by how long the computer has been in suspend mode.
I know that it is possible that this problem is due to an interaction between two or more of the applications that I use and as such it may not be able to be duplicated by others. In the end I am just wondering (a) are other people experiencing this issue and (b) does anyone have some advice on where to start looking for a solution if one is not already known. I am even open to the idea of switching to the beta release of 12.04 if anyone thinks it will solve the problem.
Edit: I took a video of my latest freeze that you can watch at http://youtu.be/flKUqUzCmdE, sorry about the audio.
Edit: Since that video I checked my memory for errors and tried installing the proprietary video drivers. No memory errors were found and the proprietary video drivers made the display unusable so I had to uninstall them. Any thoughts?