Well, I eventually got the latest Catalyst Beta to work with my nMP (6-core, D500s) and, WOW, GTAV at 1440p, very-high-everything settings is INCREDIBLE. An absolutely flawless crossfire implementation. 60FPS, solid, no stutter. Here's how (I think) I did it: - remove all drivers with DDU; - unpack Catalyst Omega drivers; - unpack latest Beta drivers; - unpack December 2014 Bootcamp drivers; - replace the entire contents of the Bin64 subdirectory in the Beta drivers' directory (in c:\AMD\) with the entire contents of the Bin64 subdirectory of the Omega drivers; - replace the Installmanagerapp.exe and installmanager.dll files in the Bin64 directory of the Beta drivers with the same files from the Bin64 directory of the December 2014 bootcamp drivers; -run setup.exe in the beta drivers unpacked directory. I lost my catalyst control panel in the process (despite registry cleaning) but, who cares about that if crossfire no longer needs to be switched off for GTAV??? Good luck!