I am using a 4550 ATI card and it works well. Because I have a AVR I ran optical out from my sound card to the AVR and the HDMI directly to the TV. Why, because I was having handshake issues with the PC-AVR-TV.
As far as being washed out maybe it is your adapter. You might be able to fix the image via the Catalyst Control Panel or look at a new adapter.
