I'm also having this problem on Ubuntu 12.10, it takes a day or two to bring my 4GB RAM system to a crawl, and I'm using no nvidia driver but Intel(0): [DRI2] DRI driver: i965
This is a serious problem that I can only solve (and continue working) because I know how to get to a shell and kill and restart gnome-shell.
I'm also having this problem on Ubuntu 12.10, it takes a day or two to bring my 4GB RAM system to a crawl, and I'm using no nvidia driver but Intel(0): [DRI2] DRI driver: i965
This is a serious problem that I can only solve (and continue working) because I know how to get to a shell and kill and restart gnome-shell.