AMD HD7000 Series Crossfire Problems/Solutions...

Ok so, I just bought two HD7770s for crossfire to replace my 3 year old HD5770s, the only problem is they don't work. And no, it's not a hardware problem, in case you were getting ready to RMA. Save yourself the time and the shipping costs because this is a driver problem. The first driver that supported HD7000 series cards was Catalyst 12.3. As I understand, that is the only version of the driver which currently doesn't freeze up in directx 9 games (most notably The Witcher 2 or the dx9 mode of Crysis 2). You may want to check out the forums at GOG or Steam for several solutions to the Witcher 2 Enhanced Edition freezing problem. Ok so, if you just updated to Catalyst 12.4/12.6 or 12.7 beta, you may have this problem wherein if you try to play The Witcher 2, a couple of seconds into the game your computer freezes and your screen either displays horizontal colored lines or black screen (this is the same for Crysis 2 dx9). There are several solutions to this problem: 1) Disable crossfire in the control center 2) run the game on a lower 16:9 resolution, e.g 1600x900 3)run the game in windowed mode. The problem is you are not going to like these solutions, which prevent you from playing the game in it's full HD glory. But you are going to like the final solution: Disabling ULPS. Yes, that's right, you are going to have to edit the Windows 7 registry. Fortunately, this is way easier than it sounds. All you have to do is type "regedit" in the search bar in the Windows 7 Start menu and under the "edit" menu (in the regedit window) you'll see the option "find..." click on that and type "ULPS." let it search for a moment...a list should come up and the value "enableULPS" should be highlighted. Right click on that value and select "modify" and in the box labeled "value data" change the 1 to a 0 and click ok. Click out of regedit and onto the Windows desktop, restart your computer. You are done. Next time you play the Witcher 2 with your brand new HD7000 series cards, it shouldn't freeze anymore, crossfire and all. Note: if you ever want to revert just go back into "regedit" and change "enableULPS" back to a 1 again. Otherwise, you may want to keep it that way, until the new fixed driver comes out.