What's the pc specs?
Latest GPU drivers?
Have you checked the event logs to see if there's a reason given for the crash?
Try turning AA off when you change the settings.
Let us know *crosses fingers*
Also you're not turning on mantle are you?
Mantle is AMDs version of DirectX afaik it's not supported on pre 7000 series cards. It was going to be my next suggestion but doesn't matter now .
Erm if I'm honest I don't really know how AA works but it seems to be a problem with the drivers and the 69xx series. Hopefully it will get sorted but you're not missing much .
No worries at all . Add me on battlelog and join us in some games if you want .
Myn1ght
You're abadoning AMD . 970 is a monster of a card it will serve you well .
Completely understandable. Crossfire as great as it is seems to have a few annoying issues every now and then.