SiS driver display problem

I've installed Ubuntu 8.04 on a new machine, and with a resolution of 1280x1024 the screen comes up very corrupted, with horizontal bands shifted to the side. Dropping the resolution to 1024x768 isn't so corrupted, but I get a lot of sparklies still. I need to drop it to 800x600 to get a decent image. I've also tried a live boot of Fedora 8 and this displays exactly the same problem. The adapter is shown as being: "silicon integrated systems [SiS] 661/741/760 PCI/AGP or 662/761Gx PCIE VGA Adapter" The selected driver is a silicon integrated systems driver, but it's not specifically specified for any particular card. I've looked at the downloads on the SIS website, and all they have on offer for Linux are some five and a half year old drivers for drivers for RedHat 7.0 and 7.2 Is there any way I can cure this problem and get 1280x1024 working on this machine? Quite happy to try a different distribution if it would help as this is a virgin new machine so can easily be totally wiped and restarted. Although the fact Ubuntu and Fedora both display exactly the same problem doesn't seem encouraging. P.S. I'm a total linux newbie, so please not to try and baffle me too much, and apologies if I'm missing the obvious somewhere.

what he said. and perhaps try setting the display frequency lower(or higher). one distro set my display frequency at 80 or so MHz whiel my monitor could only handle 67. It was an old monitor :/