Another question is are you overclocking your Athlon at all?
I have a similar setup, and I was running my Athlon 700 overclocked to 800.
For some reason AH didn't like this in the least and I would get dumps to desktop and the occaisonal freeze.
Set it back to 700 and not a single problem. Of course it wasn't like I needed the additional speed for AH so it wasn't a big deal.
Good Luck
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"