The resolutions changed because your monitor was not being detected properly on hardy, so you got a set of generic default resolutions. That issue got fixed in intrepid. Jaunty improves a bit further and may provide a few more additional resolutions.
Basically this is a dupe of #283986; see https:/ /bugs.freedeskt op.org/ show_bug. cgi?id= 17215 as well.
The resolutions changed because your monitor was not being detected properly on hardy, so you got a set of generic default resolutions. That issue got fixed in intrepid. Jaunty improves a bit further and may provide a few more additional resolutions.