My mom has a Dell Dimension 4500. The video card is finally going I think. The screen kinda flickers. The card she has in it now is a GeForce4 MX 420 64mb. Can I put my Radeon 9550 256 Mb in her motherboard? I don't know if the motherboard can handle it cause I think hers is running at about 264 MHz and my Radeon 9550 is 400MHz. I can't find upgrade specs. for it anywhere. If someone can please help me I would be greatful.