Display blinking to black on HD3850

[manimal29]

The particulars:
Intel E8400 processor
Gigabyte GA-P35-DS3R motherboard with F10 bios
Two 1GB sticks of Corsair XMS2 PC6400 DDR2 ram
Windows XP Pro w/SP2
Visiontek HD3850 256MB video card
No overclocking whatsover!
Without rhyme or reason, the display will occasionally "blink" to black for a second, and then return to normal. It can happen under a full load, or under minimal load, without any apparent pattern. No particular program or task seems to affect the random nature of the occurrences. There is no artifacting under load, or anything else that seems to be wrong besides the blinking of the display. Any and all help is greatly appreciated!