I recently purchased a BIG 6600 256 MB card (low budget, or I would've gone for the GT). It works all right, but it has the following problem. In Windows 98 and XP, I've set the refresh rate to 70 hertz, which is fine. The display never flickers. But when I load a game--Half Life 2 or NFS: Most Wanted Demo or Quake 4--everything from the menu screen to the actual in-game graphics have two horizontal lines running down the screen. The kind we usually associate with lower refresh rates. I tried forcing the refresh rate of games to 70 and 75 hertz using DirectX's override (in the dxdiag.exe's More tab), but the problem persists. I have Forceware v77.00. What could be causing this problem? My power supply is rated 300. This problem only springs up in games--even old DirectX seven games like Deus Ex. The Windows display--including movies--is fine. So I don't think it's a monitor problem. I tried browsing through the stickied All Graphics Card Queries Here thread, but didn't find any useful suggestions. Please help.