I had a problem with sluggish graphics and the "nv" driver, as well, some time ago. See bug 27919 for details on that. The problem has long since gone away, though, so the two may be completely different issues.
Did your same computer have problems with any other Ubuntu versions? Or other Linux distros all-together? That might be the first thing to try... Here are the details for my graphics card: 01:00.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX 5200] (rev a1) -- 2d sluggishness with 'nv' driver https://launchpad.net/bugs/86617 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
