I used the Catalyst 11.2 .run and have diablo running again however it "Added Cypress (#x)" with x being 1 thru 4 of 14 CU each. there are 2 HD5830s in this machine. I've never seen this before. The driver installed was ati-driver-installer-11-2-x86.x86_64.run that I restored from a backup.
If I don't use the .run scripts from AMD/ATI then I'm not sure how to install the proprietary drivers. However it's mining and at a touch over 553 which is where this machine has always been.
My /etc/X11/Xorg.conf file is as it's always been since 6 of 2011 so it didn't add devices 3 & 4.
PS: Diablo that is running now has a .jar file dated Jan 23rd of this year. I tried the 11 March one with same results but it is reporting around 537 mhash