No DVI/HDMI converters, using HDMI to DVI cables. I'm not usre it's the 990, in fact I'm pretty sure it's not.

I was thinking it might be worth switching the connection to component and see if the artifacts are still there. That project just involves recabling, furniture moving, etc so it might be a week or two.

Ahh, interesting. Do you have any kind of sharpening or smoothing or any other kind of picture "enhancement" features turned on on the TV?

You might try turning all that stuff off if it isn't already and see if it makes a difference.

Nope, it's all turned off.

Heh, in that case, have you tried turning any of it on to see if it makes it better or worse?

hehe, yeah. There are only two post-processing modes and I've tried them in various configurations with no effect