Hi i recently purchased an amd a8-3870k apu. It has been nothing but trouble trying to get the thing installed but i finally got 64 bit ubuntu 11.04 installed because 11.10 doesn't support my radeon 6550d graphics card. Anyways i installed the catalyst driver for my card so i could get unity to work but now i can no longer switch users. It freezes at a black screen. I removed the catalyst driver and used the ubuntu driver and i was able to switch users but unity no longer worked. I was wondering if there is anyway to fix this.