Recurring 65 second Spasm

Now this is one of the weirdest problems I have ever seen.

My son bought a hot gaming system and it is a dream, but every 65 sec like clockwork, the system stutters for appx 200 msec destroying audio/video/game frame rate/etc.

He has stripped it down several different ways to isolate different driver configs, reinstalled XP six times now and the appearance occurs randomly and then never quits. Virus/spyware yields zip.

The XP performance graph shows a regularly occuring spike in CPU #1 and #2 on the 65 sec boundary, but the process list is moving too fast to catch/ID any particular task as the culprit.

Can anyone suggest a way to trap/breakpoint this bugger?

Thanks for your consideration!!!
Bruce

System Data:
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Processor:
2.4ghz Intel Core2Duo E6600 (LGA Socket 775)

Video Card:
PNY nVidia 8800GTS

Ram:
2x Corsair XMS2 1g sticks (the version compatible with my board)
4-4-4-12 timing.

Motherboard:
Asus Striker Extreme

Soundcard is packaged bundle card.

PSU
FSP Group 750w PSU

Linksys WNC the wireless N model.

HDD:
WD Raptor

CD/DVDROM:
Toshiba
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