An X.Org Server update that was pushed into the Lucid repository last week has resulted in the system being slower and slower as its left on until it reaches a point where the system is no longer usable. The memory leak was tracked down to a set of patches that were made to fix some program crashes when the X.Org Server began supporting GLX 1.4.
The attempt so far to correct the patches have not worked out. In order to make the Ubuntu 10.04 LTS deadline, the developers are looking at just reverting three of the patches, which brings the GLX version back to 1.2. Ubuntu developers are now desperate for those willing to test out this updated X.Org Server package so they can determine by this Friday whether to ship it with Ubuntu 10.04 LTS or doing an early SRU (Stable Release Update). Right now this X.Org Server that's being tested is living in the ubuntu-x-swat PPA.
The bug surrounding this X.Org memory leak is titled GEM objects not deallocated in reference to the Graphics Execution Manager. There's also details surrounding this troublesome regression on the Ubuntu Wiki via the GEMLeak page. A message in regards to this problem has also been written to the ubuntu-devel mailing list classifying this as an urgent problem.