Playback Jittery over HDMI, ok over VGA

[gferrazzano]

I just built an HTPC and noticed that video playback is a little jittery over the mobos HDMI out but is fine over VGA. Is there a reasonable explanation for this? It's not a huge deal as I am ok using VGA but it would be more convenient to use HDMI.

Also, if I am using VGA, I can correct the overscan on my tv in XBMC but not in Windows, the NVIDIA control panel option only appears when using HDMI. Can anything be done about this? Would a custom resolution work? I'm a noob, and don't want to blow up my TV.

Some stats:
ASUS P5N7A-VM 775 GF9300
CPU INTEL|C2D E8400 3G
2GB RAM
BLU-RAY COMBO LG|GGC-H20LK

[Hitcher]

What's the TV? You might be able to turn off overscan.

[gferrazzano]

Sony KDS-60A3000

[stoli]

I'm running the same mobo with an Intel E7300 using HDMI with no problems. Initially it was under Vista and now Windows 7 with Vista nVidia drivers.