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Topic # 21214 19-Apr-2008 13:26
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As the on board X1250 graphics of the ASUS M2A-VM HDMI motherboard weren't quite hacking the pace on TV3 DVB-T (75% CPU load) I took the advice of various geekzone threads and installed an HDMI capable video card.  Firstly the ATI 3450, once installed it produced huge blocky artifacts and horrible noises so I uninstalled it and took it back, I noted that Nvidia cards were suggested on some threads.  Waiting a couple of weeks I installed a Leadtek 8500GT and the same problem immediately appeared again.  But when I played some TS. files recorded with onboard graphics only they were smooth and clear.

When I forced the second HVR-3000 to operate as the primary card it was clear as a bell, and the picture smooth.  It was only then I twigged to the fact that the layout of this particular motherboard puts the PCI-Ex videocard's processor etc about 5mm (or less) from the tuner circuitry on the HVR-3000 in the No1 PCI slot.  And that the No1 HVR-3000 screens the No2 HVR-3000 (in PCI slot 2 right next door) from the video card. To test the theory that EM interference from the videocard was the issue I built an EM shield by sandwiching tinfoil between two layers of insulating plastic and placing it between the videocard and the No1 HVR-3000 (being careful about cooling flows).  And the interference vanished.

So I post this as a word of warning to potential HTPC builders.  Look carefully at the location of PCI-Ex and PCI slots if you are going the multi-tuner route.  The M2A-VM HDMI is a micro-ATX board with the slots all close together, and with the benefit of hindsight an ATX board may have been a better bet (like an idiot I bought a 'nice' looking case first - for WAF - only to realise it was a micro-ATX, which limited my choices from then on).




Areas of Geek interest: Home Theatre, HTPC, Android Tablets & Phones, iProducts.

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  Reply # 124953 19-Apr-2008 17:25
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Dingbatt: As the on board X1250 graphics of the ASUS M2A-VM HDMI motherboard weren't quite hacking the pace on TV3 DVB-T (75% CPU load) I took the advice of various geekzone threads and installed an HDMI capable video card.  Firstly the ATI 3450, once installed it produced huge blocky artifacts and horrible noises so I uninstalled it and took it back, I noted that Nvidia cards were suggested on some threads.  Waiting a couple of weeks I installed a Leadtek 8500GT and the same problem immediately appeared again.  But when I played some TS. files recorded with onboard graphics only they were smooth and clear.

When I forced the second HVR-3000 to operate as the primary card it was clear as a bell, and the picture smooth.  It was only then I twigged to the fact that the layout of this particular motherboard puts the PCI-Ex videocard's processor etc about 5mm (or less) from the tuner circuitry on the HVR-3000 in the No1 PCI slot.  And that the No1 HVR-3000 screens the No2 HVR-3000 (in PCI slot 2 right next door) from the video card. To test the theory that EM interference from the videocard was the issue I built an EM shield by sandwiching tinfoil between two layers of insulating plastic and placing it between the videocard and the No1 HVR-3000 (being careful about cooling flows).  And the interference vanished.

So I post this as a word of warning to potential HTPC builders.  Look carefully at the location of PCI-Ex and PCI slots if you are going the multi-tuner route.  The M2A-VM HDMI is a micro-ATX board with the slots all close together, and with the benefit of hindsight an ATX board may have been a better bet (like an idiot I bought a 'nice' looking case first - for WAF - only to realise it was a micro-ATX, which limited my choices from then on).


That is very well diagnosed. Congrads. I do believe that when it comes to electronics, more [room] is better. What now: a premanent EM shield?




Silverstone LC14 HTPC Case/Intel E4600 CPU/GA-EP35-DS3 MOBO/Asus EN9500GT graphics/2GB RAM/total 2TB HDD space/HVR-2200 & 2X 150MCE tuner cards/LG GGC-H20L BD Drive/MCE2005/Mediaportal/TVServer 1.1.0Final/LG 55"3D LED-TV/Denon AVR-1803 receiver/X1 projector



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  Reply # 124957 19-Apr-2008 17:55
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1gkar:

That is very well diagnosed. Congrads. I do believe that when it comes to electronics, more [room] is better. What now: a premanent EM shield?


Yes I only figured it out last night and have left the machine running all day while the the Hamilton V8s are on to check on how the plastic handles the heat and there are no other cooling issues. Then figure out how to fix the shield in the case.  The 8500GT certainly make a difference, the CPU is sitting around 10% now, although I'm kicking myself that I shot the ATI 3450 back so quickly because it was 50 bucks cheaper and probably would have worked okay.

The set up above will probably stay like that for a while.  As well as connecting to the Plasma, it is networked using mediaportal TV-server to a couple of PCs.  The system seems to work well, so the tuner cards will probably end up in a purpose built mediaportal (or Vista MC - if MS ever get it right) server made with an ATX mobo in an ATX case.




Areas of Geek interest: Home Theatre, HTPC, Android Tablets & Phones, iProducts.

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