It's most odd that component video works best, as your display is a digital device and your source (DVD) is a digital format. I assum ethat you calibrated the TV's HDMI input using something like Digital Video Essentials and we're not seeing a calibration issue between inputs? In my setup (with an analog display device), the cable box's DVI and component outputs were pretty indistinguishable, but the difference between my 980H's component output and HDMI output is pronounced - and in the HDMI output's favor.