Wierd video artifacts with Win MCE 2005 OTA HD

[nollonemo]

I'm posting this here even though it might be MCE-specific since I'm at my wits end, hope someone can shed some light on this because of the high level of tech expertise around here.

I'm getting strange artifacts playing HD TV in Windows Media Center 2005:

I am getting artifacts on live view or playback of OTA HDTV. The artifacts look like red lines that appear and disappear, about 1" long and 1/8" inch thick on a 21" computer monitor. They appear both on the computer monitor and on my TV (currently 32" Sony SD CRT set, connected via S-video).

They start anywhere from 3 to 8 minutes after I start viewing/playing back, and their number increases over time until the almost fill the screen. The placement seems to be randomThey seem to be an overlay of some kind, because if I do a screen capture, they don't show up. Also, when they fill the screen, the TV image can be seen underneath them. I'll see if I can get some images up to link to.

There is no stuttering or hiccuping with the image, the playback is silky smooth, the only problem is these artifacts.

What I think so far:

1) I'm pretty sure this is a decoding/graphics card issue and not a TV card issue, because the lines don't appear if I burn a recorded HD show to DVD.

2) I'm pretty sure it's an HD-specific issue, because the artifacts only happen with HD broadcasts, digital SD broadcasts don't display the problem.

Here's my setup:

MCE 2005 w. rollup 2 & latest patch
MachSpeed P4M800 motherboard
Celeron 2.9Ghz CPU
1GB 333 DDR memory
Gigabyte Nvidia GeForce FX 6200 128MB AGP video card (64 bit)
7200 rpm ATA100 hard drives (one for OS, one for Video, both defragged)
Hauppauge 150 SDTV card
Avermedia 180 HDTV card

What I've tried so far, with the same results.
Changing between latest Nvidia drivers and 77.x drivers
Changing between latest Nvidia decoder and Cyberlink (PowerDVD) decoder
Changing PCI slots for cards
Decreasing amount of hardware accelleration
Changing monitor setups (clone vs. separate display)
Running MCE and Nvidia setup wizards

Please tell me there's a fix for this short of going to a beefier video card. A lot of people seem to be using the Nvidia 6200 card for HD with no problems (the reason I got the card in the first place)

Thanks, everyone!

 

[nollonemo]

It is a heat issue. Opening the case and blowing a fan into it made the artifacts go away. I did some testing, and when the graphics card core temp hits 76 degrees C (which is the first yellow bar on the GPU core temp applet), the artifacts start appearing, and get worse as the temp goes up. The card is only stressed enough to reach those temps when the signal is being sent to the TV in addition to the computer monitor. It looks like putting a case fan or CPU heatsink fan inside the closed case at the edge of the card to blow air onto the heatsink should fix the problem. Kludgy, but at least it will work.