I've been using quite a few distros trying to find one that will work with my setup. It's nothing complicated. 2 monitors, 1 connected via HDMI, the other MiniPort. The card is a Sapphire 6870 Flex. I've tried using Debian 6, not installing the graphical desktop and just installing per their ATIProprietary#Squeeze documentation and no luck. I've tried ubuntu 12.04 and 12.10... it hates allowing dual monitors without having one be glitchy(screen shake) or not allowed to de-mirror them. One monitor, fine, great, no problems, awesomeness. 2 monitors and it goes to garbage.
I'm an intermediate newbie. I work with linux every day but that's only as a server deploying tomcat and working inside of the command shell. This is my first foray into graphical linux and so far it's made me want to punch myself in the nether regions.
My question is this: Which distro, or base package, will give me the easiest time with installing my graphics card and not having 99 problems, being slow, or looking like garbage? If I have to download one and install drivers, I'm fine with that, as long as they work.