Media Center Playback from central storage freezing

Got a strange issue. My setup is a Main Media Center system used for recording shows. This system shares its recorded tv folder with other media center clients. The Main system is also host to a Ceton Echo extender. The systems have been working fine for years. After a recent power outage, which also triggered an MS update, when the clients try to playback from main server disk storage, i get random freezing. The freezing halts video for a few seconds, then appears to play slow motion for a few seconds till its seems to catchup. If i switch to Media Player on the client the same show plays fine. This only seems to be a problem when using Media Center to view shows. Copying files between system is fast and consistent, around 90MB/Sec. Gigabit network throughout.

If i move file to local storage on the clients the same show plays fine. If i watch the shows on the extender, which is hosted by Main media Center server, playback is also fine, no stutter. If i try watching a show stored on a client system back on the Main Media Center screen, all plays fine. I only see this issue when clients, which are Media Center also, try to watch shows stored on the Main Media Center system. All systems a Win7.

I have rebooted all network devices, updated network drivers with no fix. Not seeing any disk issue on Main system. I suspect something in the MS update tilted the system, and i'm unable to access a restore point.

HomeGroup is used for storage sharing.

Not sure what else to try other then reinstall, which i am trying to avoid.

Any ideas?

Not sure why this fixed the problem, but i installed a different video card on the server. One i did that the clients started playing back main system stored recording without any freezes. The MS update must of muked up drivers or something. Anyway back to normal. Hope this might help someone else.