Opteron 246 retail - is the fan temperature controlled?

At work I use a dual-Opteron 246 (2.0GHz Clawhammer, retail boxed)
machine with a Tyan Tiger K8W (S2875) motherboard. The computer is
acceptably quiet when I first turn it on (CPU fans at 3500 RPM according
to Tyan System Monitor), but after it's been up and running for awhile,
the CPU fans wind up to a deafening 6500RPM.

My question is, is the motherboard doing the speed scaling, or are the
fans themselves thermally controlled?

If my machine were in a noisy server room, I'd probably prefer a louder
and cooler machine, but sitting on my desk, I wouldn't mind trading an
extra 5-10C for a little sanity. FWIW, the CPUs typically sit at 42C
under load, so it seems there should be a little leeway. The case is an
Antec tower with dual 80mm case fans (themselves not silent but not
annoyingly loud either), for what that's worth.

On Wed, 27 Apr 2005 19:35:59 -0600, Lachoneus wrote:

If my machine were in a noisy server room, I'd probably prefer a louder
and cooler machine, but sitting on my desk, I wouldn't mind trading an
extra 5-10C for a little sanity. FWIW, the CPUs typically sit at 42C
under load, so it seems there should be a little leeway. The case is an
Antec tower with dual 80mm case fans (themselves not silent but not
annoyingly loud either), for what that's worth.

I replace the small somewhat noisy fan with a 70-80mm fan adapter and an
80x25mm 2500rpm fan. No more noticable noise. Cools about the same

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