envision display card driver

I'm trying to find a display card driver for my Dell 546MT desktop w / Envison EFT9X0 display card. This card is not listed as a choice at the Dell video driver download area and the Envision web site refers only to their monitors. Did Dell sell me a desktop with an outdated display card? It's only a couple of years old. The screen resolution spontaneously changes during hibernation. It was suggested that I update my driver. Any ideas?

Thanks , Paul