System Failure or the Capture Card?

[ses]

Not sure where to place this question, but here goes. My capture card is the Compro Videomate Gold Plus II TV card, the graphic card is the Matrox G400. I have an MSI 845PE Neo series mainboard, the model number is MS-6580 Version 5.0. the processor is a Pentium 2.5 and I have 512MB of DDR. A Soundblaster Live sound card and a Seagate Baracuda 200GB for recording only. I use the iuVCR recording program with the Huffyuv codec and I am using W2000.
I have a problem with dropped frames. With my old nVida based MSI Personal Cinema, I had no dropped frames, ever. Even when recording VHS. The problem with the nVida card was that it was dreadful at recording NTSC video here in PAL Land. (Sweden in my case)
The Compro card is far better at it giving an excellently reproduced picture even before I add filters, but I get exactly 23 dropped frames for every hour of recording.
Each dropped frame comes at exactly the same moment. The first frame drop will always at 1:31 into the recording. The next frame drop will always be at 4:30 into the recording. You can set your watch by it! When I start iuVCR for the first time, it will count the dropped frames from 0. If I close iuVCR, open it again and begine a new recording project without restarting the computer, it will start counting the dropped frames from where it left off before and the time intervals and number of dropped frames continues with the same predictability.
I am no expert, but it's my guess that something in the system is causing this, but what could it be?
If there were randomly dropped frames all the time, then I would tend to suspect the card. But the fact that they always happen at the same time every time makes me want to look elsewhere in my computer. I tried recording with and without the computer connected to the network and there was no difference there either. There is no difference if I use XP either.
Doing the harddrive test in Virtual Dub, the harddisk checks out fine too.
Anyone have any ideas?

[landrover]

It could be some background process taking PCI bandwith or CPU power at set times, but it's also very likely that the dropping is done on purpose to maintain good A/V sync. If the last case is the fact, you should actually be glad that it does that.
Have you tried capturing with as many processes shut off as possible, like firewalls, virusscanners, messengers or mail-clients?

[Flying dutchman]

It could even be caused by a quartz frequency issue; I had two identical Soundblaster PCI cards. With one of them, I suffered from dropped video frames during capture (about 1 frame per 4 minutes). With the other, capturing went smoothly. I assume that one of the sound cards had a slightly inaccurate quartz frequency so the capturing software had to drop video frames to keep the two in sync.

[ses]

Thanks Gentlemen for your comments. Interesting point about the sound card. I imagine that I could test that by, at the very least, disconnecting the Soundblaster that I have and see how it reacts with the original on board sound though there is no such reaction with the nVidia card.
I have tried it with the network shut down, this computer has no email program in use, it doesn't even go out on the new and has no antivirus progrmas either. A friend of mine created a Windows 2000 "lite" that had everything possible removed that wasn't needed, still the same problem came back. It also occurs with XP.
By the way, can anyone explain "Video Latency Stream" to me. Is it better to have a higher figure or a lower one. The nVidia card always seems to have a figure up over 100ms even though it's never the same number twice in a row.
The Compro card seems to have a lower figure, between 50 and 60 ms.