Thanks for the replies.
None of the HDDs are nearly full, and all of the issues I'm having a with live playback. Most of my files are only divx rips, and they look exactly the same on my MacBook and HTPC, I think in those cases, it's just a poor file, and I've never noticed the symptoms on the smaller MacBook screen.
I haven't looked at CPU/GPU usages no, can you recommend a tool to monitor them?
The company who makes the tuner made me run a test using DVB Dream and streaming to VLC media player. I still had the same issues, but the analyser in DVB Dream showed no errors on the stream.
Below are the following things I have tried. (When I say ATI Graphics, I mean the HD5450 I have been moving between the two PCs). All GPU's have been using the latest drivers, and when from Intel to ATI and vice versa, I always uninstalled drivers.
New System - Intel Graphics, DVB-T2 tuner, Media Center - Still got issues
New System - ATI Graphics, DVB-T2 tuner, Media Center - Still got issues
New System - Intel Graphics, DVB-T2 tuner, DVB Dream and VLC - Still got issues
New System - ATI Graphics, DVB-T2 tuner, DVB Dream and VLC - Still got issues
New System - Intel Graphics, DVB-T2 tuner, TBSViewer - No issues, but very poor picture quality
(The above are exactly the same on an x64, and x86 Windows 7 Install)
Old System - ATI graphics, DVB-T Tuner, Media Center - No issues
Old System - ATI graphics, DVB-T2 tuner, Media Center - Still got issues
New System specs - Intel Pentium G620, OnBoard Intel HD Graphics, ASUS P8H61-M Pro Rev 3, BeQuiet L8 400W Modular PSU.
Old System Specs - Intel Core 2 Duo E6750, ATI Radeon HD5450, ASUS P5K-E WiFi-AP, OCZ 600W PSU
Both systems uses the same hard drive for the OS, except the new build has an extra 7200RPM Seagate Barracuda 2TB in it.
My old system works perfectly fine with my other Dual DVB-T tuner (the new one is DVB-T2). I cannot test the old tuner in my new system, as it's PCI and not PCI-E. To me, the above says that it's an issue with the tuner itself, and/or drivers.
All of the above tests were done with live TV.