Cyclical drop in CPU usage

[galiman]

When I first fire up GBPVR it works great for about 5 to 10 seconds with CPU at 25 to 30%. Then CPU usage drops to 0 to 5% for gbpvr.exe, with system idle at 95+%, and video becomes basically a still frame with occasional annoying squeaks in audio. Then after about 10 or 15 seconds, gbpvr.exe CPU usage rises to 25 to 30% and picture and sound is great. And again, after 5 or 10 seconds, CPU usage for gbpvr.exe drops again... and cycle goes on. It's almost like the computer just quits running GBPVR for a few seconds, then starts it back up, then stops it, etc.

Is this indicative of a common settings mistake? I have re-loaded WinXP 3 or 4 times, am using most recent drivers for MB, cards, etc. I know it sounds like a codec issue, but does the cpu usage drop like that for a codec problem? It seems to me the cpu usage should spike for codec issues.

My system is Athlon 64 3500+, Asus A8V-MX motherboard, 1 gig RAM, ATI All-in-Wonder 9800 video card (only used for component out, not as TV tuner), ATI Theater 550 Pro, and ATI HDTV Wonder. I have ATI multimedia center installed, so I know I have what should be the best codecs (Cyberlink) for these cards (although I have tried others, including Elecard, Intervideo, and DScaler).

Any suggestions? Thanks in advance, and I apologize if this has been answered before.

[sub]

zip and attach the logs and I'll see if I can see anything obvious.

[galiman]

Thanks for looking Sub...

Doesn't seem to want to upload .rar. Do I have to have .zip?

[galiman]

Sorry to bump this tread, Sub, but I was wondering if you had had a chance to look at the logs, yet. I really hope you find something, because I have no clue (not that I'm an expert or anything).

Thanks again.

[sub]

Sorry, I cant really think of reason for this. The logs look fine.

[pastro]

I assume you have tried changing slots for the capture card? What sort of shared interrupts are there?

[galiman]

I have changed PCI slots for the cards. All heat reduction software is disabled, but it's not needed, as CPU temperature is displayed on front panel LCD and is very stable.

Thanks for everyone's replies. I think this is not a GBPVR issue, but something amiss with the computer itself.

[galiman]

I let the loop run for about one minute. CPU stayed pegged at 100%.

[galiman]

That's a good question, but one I cannot answer. The HDD case light has never worked properly, could be confused by the fact that I have three hard drives installed.

If you think of anything else, I'm all ears, especially concerning processes that may throttle the CPU up or down. I hadn't thought of that until you mentioned it. In the meantime, I may start shopping for a replacement motherboard.

[galiman]

Well, I'm very close to a solution, thanks to you mvandere. Your idea about the HDD light started me thinking about how much power I was using with three hard drives (plus a DVD drive), so I disconnected all but the c: drive, including the CDROM. GBPVR worked like a charm, CPU stayed fairly steady at about 40 percent.

So that narrows it down to either an insufficient power supply, a bad IDE drive or cable, or a bad secondary IDE channel (motherboard), all of which can be fairly easily fixed. It's too late here and I'm too tired to follow up on it, but at least there's light at the end of the tunnel.

Thanks mvandere and sub for responding to my questions.