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Old August 7, 2011, 08:05 PM
frontier204 frontier204 is offline
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Join Date: Nov 2008
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My System Specs

Default Folding on CPU decreases choke whine from GPU?

Hi all,

The title says it all:
I got a GTX 550Ti for my "My System Specs" rig after discussing in this thread. The card has a very quiet fan - comparable to case fans - but it emits a high-pitched whining sound while folding, probably from chokes.

I found something odd while measuring the new F@H PPD / Watt of my main rig which has said GTX 550 instealled. If I fold SMP on my CPU + GPU3 on my GPU, the whining sound is much quieter than when I'm folding GPU3 only. If I fold GPU3 only, the whining sound is very noticeable, and annoying because it changes frequency often. However, If I fold with both CPU and GPU, the whining sound decreases to the point where I barely notice it. The SMP doesn't seem to be starving the GPU client, as the PPD reported from HFM.NET is about the same as folding GPU only, and just to make sure I raised the priority of GPU FahCore_15 to "below normal" while the SMP is at its default "idle" priority.

Can you offer any explanation to this black magic? If I fold GPU only, I'd have to underclock the card to somewhere around 825-850 core to quiet down those chokes to the same point as if I were folding with CPU + the GPU at its normal OC of 970 core. (memory clock doesn't affect the whining, and shader clock is locked to Core x 2)

Essentially my rig now gets QUIETER if I fold more on it! ...how does loading the CPU make my GPU quieter?
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Last edited by frontier204; August 7, 2011 at 08:06 PM. Reason: my usual "that sentence just doesn't look right" edit I make 30 seconds after posting
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