they consume about 75-watts of power

Ouch! That's about the same as a T-Bird 1.4GHz, which IIRC was about the hottest-running Athlon produced.

So an AIW 9800 and a T-Bird 1.4 would put you at 150W disippated into the case. Add a drive or 2, a couple of sticks of RAM, and the motherboard chipsets, and I can easily see 250W into the case.

How is your case cooling?
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