For quite some time now I have been using the same board on a diskless MD without any problem. I don't know which processor you have but I have the AMD 7750 Black Dual-Core CPU on mine and I don't have any problems with video. I am presently now using the Basic Titanium Menus, only because there is still a bug in the UI2's ability to see multiple floorplans. When I was using the UI2 with or without Alpha-Blending, I had no problems whatsoever.
I am also using the HDMI connector without audio, and I have not not ever worried about that because I send the audio straight to my surround receiver by way of the ASUS's optical Toslink fiber output.
I'm also using the nVidia, 180.xx driver, stock from the repository, with no lag or tearing.
Check what processor you have on the MB and maybe another gig of memory may help. Oh yes, I have 4 gig of memory, an overkill, 2 gig should do it OK.