I have this super old Thinkpad T61 and installed Ubuntu 14.04 on it. I noticed X11 is quite unstable. It'd freeze all the time, especially after suspension. Sometimes dash would appear as a blue screen, etc, etc. I have tried Xunbuntu as well. It's pretty much the same. But I don't seem to have problem with Debian 7.5. I still prefer Ubuntu to Debian. I just wonder which build of Ubuntu would have similar video/X versions as Debian 7.5. Thanks.