ATI HD4850 Graphics Rendering Issue

I bought a Sapphire ATI HD4850 a month ago and it was runs fine on games like Oblivion and Gears of War. A week ago, I installed Supreme Commander: FA. The game loaded fine and was okay until I started a skirmish game. After the loading screen, there was excessive flashing and screen tearing into random sized polygons which made the game unplayable. (The in-game user interface, audio and FPS were not affected)

This happened again in SPORE after I exited the cell stage and evolved to the land creature stage. The game was fine up until then (Game audio, creature creation, menu screens and user interface).

I've already played a bit with the in-game settings and CCC settings, with no improvement or elimination of the problem.
Does anyone else also have this problem?

I'm currently using a Intel E8400 3.00GHZ

4GB of RAM with a 600w PSU

I checked on the system temps and there seems to be no signs of overheating.

Here are a few screens, the first being from Supreme Commander and the second and third from SPORE.

update your drivers, if that doesnt work try your video card in a friend computer with the same game and see, if the problem persists just RMA your video card, it could be damage. or restore to factory defalults, also it could be that the game is bad.