OK - I've been investigating this a bit. The best site to go to is
www.driverheaven.net for more information.
As it stands at the time of this post, 5680 owners have the following options if you want a later driver:
1.You can download the ATI catalyst drivers. They won't install, but then you can run the mobility modder tool to patch them to run on a 5680.
2. You can download the Omega drivers, which are already patched for mobile chips.
3.You can download another modified driver, but I am not sure which ones have mobile support.
As of today, I found that the Catalyst 4.7 drivers work OK, but I get Doom III problems still. The 4.8 drivers and the 4.9 drivers work even better in Doom III (fast and no problems), but DVD playback does not work.
The Omega drivers are supposedly faster than the unmodified ATI drivers, but the 4.7 based Omega driver does not work with DVD playback either.
Make sure you have a system checkpoint before installing drivers, and restore if your system breaks.
Links are on
www.driverheaven.net