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I have a Radeon HD4870-based Sapphire card in my desktop PC (Windows 7 64bit) that started getting pretty noisy recently. The temperature reported in Catalyst was hanging around 80C and the fan would alternate between 43 and 46% when idle at desktop. I decided to take the card apart to vacuum out the dust from the fan and heatsink, and to reapply thermal paste.

After that, the average temperature dropped to around 70 when idle, and the fan works around 24%. But it still keeps jumping to 29% all the time and it's not as much the noise level, as the unevenness that is annoying. I installed GPU-Z and this is what I saw:

GPU-Z window capture

As you can see, the fan speed keeps changing at irregular intervals. What makes me wonder is the constant alternating of the GPU clock between 500 and 750Mhz when the machine is idle.

There was a bug in this card that made the GPU switch clock speeds very quickly in high performance mode which caused it to crash when playing games etc. I applied the bios update for that and the issue was resolved. Not sure if this is related.

Can I do anything to stabilize the clock rate and (hopefully, as a consequence) the fan speed?

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Download the latest Process Explorer version, run it and go into the System Information dialog. Here is a GPU graph, look which Tool uses the GPU and causes your issue (hover the mouse over it to get a tooltip).

enter image description here (Image source:

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Good tip; however the only process using the GPU was dwm.exe (the Desktop Window Manager that is a part of Windows), and the usage was hanging at a steady 0.02%, nothing that would explain the behaviour of the clock. – neuviemeporte Feb 22 '13 at 20:32
do you run other WPF or Direct2D applications in background? – magicandre1981 Feb 23 '13 at 6:13
No, I am paranoid about background apps and disable everything that is not necessary (anyway, wouldn't Process Explorer show the usage as well?). While I was doing the test, no applications were running except for GPU-Z itself (or Process Explorer). – neuviemeporte Feb 23 '13 at 10:05
which driver version do you use? Try different drivers. – magicandre1981 Feb 24 '13 at 17:04
I was using Catalyst 13.1 directly from AMD. Downgraded to 12.4b from Sapphire website, no change. – neuviemeporte Feb 26 '13 at 19:29

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