I recently upgraded video cards from a ati radeon 9600 pro to a gigabyte nvidia 6600gt and I'm not noticing the performance increase I thought I would have, and in some cases it runs some games worse. When I bring up the VGA utility that came with the video card, it says the VGA speed is 4x, when the card and my motherboard are both capable of 8x speeds. When I go into Bios it won;t let me adjust the AGP speed, is just shows it as running at 8x. but greyed out and won't let me change it. I just updated my bios and my motherboard is an asus a7v8x-x. If anyone else had similar problems and solved them help would be much appreciated.