Audio stuttering problems when watching NZ Freeview on HTPC

Hi all

Ive been having troubles with my HTPC and any Freeview broadcast.

Im not too sure if its the broadcast, a hardware or codec problem.

Firstly, when watching Freeview (any program, on any channel) the audio starts to stutter and eventually goes silent (quite frequently). In order to get the sound back in sync I have to pause it and play again.

Secondly the picture goes pixelated then goes to a black screen with no audio or anything, once again the way to fix it is you have to press pause and play again.

Both of these things happen when watching live TV, but doesn't seem to happen on recorded or chase play.

The problems started when I was forced to upgrade my hardware as what I believe the PCI-E slot failed.

Both systems are running Windows 7 Ultimate 64bit and inbuilt Windows Media Center

My upgraded setup is:
- Intel i3-2100 3.1ghz processor
- Asus P8H61-M Pro motherboard
- 1 x 4gb Ram
- 550w PSU
- Shark007 codec 32 and 64 bit is installed for MKV playback
- Clean install of Windows 7 Ultimate 64bit
- WPI of 4.9

Carry over components from previous system:
- Geforce 210 video card 512mb
- OEM SATA 160gb hard drive
- 2 x USB tv tuner sticks (AverTV a825 and PCTV 73e) to receive Freeview (3 x tuners)
- USB IR receiver
- OEM Compaq SR1925 case

When watching Freeview HD CPU usage is no more than 10%

My previous was a Compaq SR1925 home PC and have upgraded it with:
http://h10025.www1.hp.com/ewfrf/wc [...] ct=3264569
- Athlon 64 X2 3800+ processor
- 1 x 512mb, 1 x 2gb, totaling 3gb Ram
- 2nd 320gb hard drive
- K-Lite codec pack and CoreAVC for MKV playback
- WPI 3.8

Other components in my system are:
- Sony 40" LCD TV (connected via HDMI)
- Pioneer VSX915 amp (connected via digital coaxial(old system) / optical (new system))
- Harmony One remote

I live in Wellington, New Zealand and receive good signal from Mt. Kaukau tower using an external UHF aerial

Iv caught the problem on video and have uploaded it to youtube

http://www.youtube.com/watch?v=89C [...] e=youtu.be

Hope this can narrow it down the problem

Thanks in advance

Dave