Hi Burrows,
The flickering issue is affecting a lot of people (like us) that have a ATI Chipset that includes 4850, 4870 since they are utilizing the same type of engine.
I have seen a lot of people stating the issue is due to a overheating problem which is a bunch of crap since it is only isolated to this game and a lot of people would have defective cards.
I like most of you have spent most of my weekend trying various things to determine what could resolve or stop the flickering. When running ARMA 2 in a windowed mode I do notice that it does not occur as often, you may want to also try this for the short term.
For the long term then BIS should stop expecting people like us to beta test their product. When I buy something (especially software) then I expect defects but not to this degree this is just poor quality and poor business ethics.