With AMD the MSAA options are multi-sample, adaptive multi-sample and super-sample. These settings will not override aplication settings if the AA settings at the top of the page are set on "use application settings".
BTW, AFAIK ATI Tray Tools is not actively maintained anymore and may better be not used with current-gen hardware.
And Phusius, are you sure you saw lag when playing HM:BM? On your setup there should not be any, unless you are using an framerate counter that showed a drop from say, 100 fps to 80 fps.
I may have a lower screen resolution, but still can play that game maxed out on a HD 6670.