So I finally got my F3 Goty to work, but when I play it with the HDR turend on it makes this extremely annoying light flickering. There is some simple solutions like turning of SLI or other similar things. But it seems so half finished and goes on the cost of the performance. So if there is a patch or something that could fix this it would be optimal.

Video that shows the problem:http://www.youtube.com/watch?feature=player_embedded&v=QZDbZQZcEo0

Most likely a fix would be in the SLI profile / graphics driver. HDR flickering seems to be very common on multiple GPU systems. There are various solutions (not fallout 3 directly) involving enabling V Sync in the application, but disabling (allow application control) in the GPU's driver manager. Also increasing the frame buffer may correct it. Again, I didn't see any information for fallout 3 solutions.

The first thing I would do is update your graphics driver, if applicable.