I'm using poclbm to mine under Windows... processor is an AMD A6-3400M with integrated Radeon HD 6250G GPU. When Windows Media Player is closed, I get a rate of 16 megahashes/second, but when it is open (even if stopped or paused) poclbm reports a rate of around 33 megahashes/second.

I'm wondering if this has something to do with Windows Media Player increasing the system timer resolution, but that doesn't seem like it would affect performance.

Ideally I would like to achieve maximum GPU performance without having Media Player constantly open.

  • 1
    I can speculate that while Windows Media Player closed, video driver limits fan speed and clock rate to reduce noise and power consumption.
    – Serith
    Commented Jul 23, 2012 at 4:28
  • Do you have two GPUs with automatic switching? Something similar to nvidia's optimus. Commented Jul 23, 2012 at 16:05
  • Nope, single integrated GPU. I believe it is on the same die as the CPU. All CPU/GPU related power savings features are disabled except for variable CPU clock speed, but the GPU clock seems to be separate from the CPU's clock and there are no options to change it. EDIT: In response to @Serith, the fan speed is temperature-dependent and I have it set to never turn off the fan in the BIOS (that's the only setting available)
    – okw
    Commented Jul 24, 2012 at 23:57

1 Answer 1


poclbm has not been set to alter the clock rate of your GPU. Windows media player is doing this when open and adjusts the system to what it requires.

If you specify clock speeds for your GPU via parameters or a separate application you can overcome this.

Theres a number of applications which effect clock rates on windows machines, flash player open within a browser reduces a single card of mine down from 400 m/hash to 350 m/hash.

cgminer is very easy to specify clock speeds and mine with, it adjusts them when you start the application (not when closing though).

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