I noticed that BOINC Manager (for contributing to World Community Grid) does not work any more since I installed 11.8 Catalyst Driver. I used previously 11.6 and many older versions, and it worked well.
Same problem with last 11.9.
I uninstalled 11.9 and went back to 11.6 : fine !
Same problem with either HD4650 or HD6850.
Retrieving data ...