I’ve upgraded recently to Picasa 3.9, but running it on Linux (no Windows or Mac here…). from the 3.0 version.
One issue that I had was that Picasa was constantly consuming CPU on XOrg even when doing nothing.
To solve it out just go to Tools->Options-> General and disable Use Special Effects in Interface.
Also to clear some error messages on the .xsession-errors file just disable support for the video files.