Choppy video after working fine for a year

[otterhound]

I'm running Windows 7 Media center on the following computer:

• Dell Studio XPS 8100
• Intel Core i7-870 CPU
• 8Gb Ram
• ATI Radeon HD 5770 with 1Gb GDDR5 memory
• 1 Tb Sata 2 HD
• Avermedia USB over-the-air tuner
• Blu-ray drive

I am using an over-the-air HD antenna, mounted outside.

Connected to a Vizio 55-Inch HD LED display via an HDMI cable.

I have had this setup for a year. I use it to record over the air HD programming for later viewing, NetFlix streaming and playing Blu-Ray using the ArcSoft Total Media Theater 5 plug-in to Media Center.

Up until one month ago, it did a beautiful job with this. Image quality was great and video was smooth.

Around the beginning of October things deteriorated. Video is now very choppy, especially when there is a lot of movement on the screen, such as football games. It is as if the frame rate is down to around 5 frames a second.

This occurs regardless of whether I am viewing live TV or playing recorded TV back or streaming NetFlix.

I know the antenna is fine, because when I plug the antenna into my TV's built-in tuner the video is fine.

I know it is not the Avermedia tuner, because streaming Netflix is also choppy on the PC. But when I stream Netflix directly on the Vizio (it is has a built-in Netflix app) it is fine.

Strangely, playing blu-ray through the Total Media Theater plug-in works fine. This has made me conclude that it is purely an issue with the Windows Media Center software, since the Total Media Theater software is working OK.

I have upgraded to the most recent video drivers. There is plenty of hard disk space left. There are no other applications using up CPU cycles. I have uninstalled all antivirus software.

Bottom line is that I can't figure out what caused the deterioration. The only thing I can think of is that maybe some automatic windows update change screwed things up. But when looking at historical updates I can't find any updates in the last month other than security updates.

If anyone has any other debugging ideas, I'd be grateful.

[Scallica]

What happens when you play a recorded show using Windows Media Player? or VLC Media Player?

[otterhound]

The same choppy video problem when playing through Windows Media Player. I haven't tried VLC, but will.

[otterhound]

I tried playing some *.WTV files that were previously recorded using Media Center. They played perfectly on VLC. They played choppy on Media Center. They played awful, extremely choppy, on Windows Media Player.

So now I know that Blu-Ray playback using the Arcsoft Total Media Theater plug-in for Media Center works fine and WTV playback using VLC works fine.

Playback of WTV or DVD using Media Center is choppy. Playback of WTV using Windows Media Player is awful.

[Scallica]

I suggest repeating the same tests while logged into the system as a different user.