Check your driver settings. I know my (built in) ATI Radeon HD4200 card has drivers that default to some sort of moronic underscan compensation setting if you're on HDMI. This makes everything blurry, by scaling everything down a bit. Why? Who knows.
I have no idea why it's set up like this, and everytime I upgrade the drivers, the stupid overscan crap is back on. It's been like this for years, and why noone at ATI got dragged out back and shot for it is beyond me. Well, maybe someone did, and now that person isn't around to fix it proper.
Anyway, here's some more info about how to fix this:
[WINDOWS] Worse quality on XBMC than PS3? (SShots inside) - new build
Joined: Aug 2011
2012-06-30 19:38 Post: #31