I use a resolution above 10x7 (imagine that :) using HDMI and I have been seeing issues when watching flash or silverlight full screen. The output enlarges the image too much and only shows the upper left quarter of the video. I didn't think it was a driver problem, but I had no idea what it was. This only started a few weeks ago and I hadn't installed any software prior.
Anyway, this new driver did not fix the problem.