ATi Catalyst 10.6 does not work with 4870×2 cards or Crossfire

The Crossfire problem is quite well known, but not many people are mentioning the issue with the 4870×2 – quite possibly it is broken with all x2 cards, furthermore it’s probably exactly the same issue as these are two GPUs on one card. Anyway, roll back to 10.5 until ATi fix it. My symptoms included all source engine games causing a flickering screen followed by a blue screen caused by the driver getting stuck in a loop. Also BFBC2 would only show a white screen instead of loading correctly.