I, like a lot of others have had issues with my Nvidia graphics cards appearing washed out when using the HDMI connection. This was never an issue when I used a single monitor, as I just used DVI. I have discovered that Nvidia cards are set up for HDMI TV narrow color range, not for computer monitor full color range.
I have found a solution, and my HDMI looks 100% better, brighter, and without any washed out colors.