# PCI latency timer...



## erocker (Jan 11, 2008)

So, I bought Guitar Hero III for the PC (it is awesome) and I was getting some crackling noises.  On RedOctane's website the say to put the PCI latency timer to 32, while I usually kept mine at 64.  It worked, but what does this do exactly?


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## ex_reven (Jan 11, 2008)

Found this:


> PCI latency timers are a mechanism for PCI bus-mastering devices to share the PCI bus fairly. "Fair" in this case means that devices won't use such a large portion of the available PCI bus bandwidth that other devices aren't able to get needed work done.
> 
> How this works is that each PCI device that can operate in bus-master mode is required to implement a timer, called the Latency Timer, that limits the time that device can hold the PCI bus. The timer starts when the device gains bus ownership, and counts down at the rate of the PCI clock. When the counter reaches zero, the device is required to release the bus. If no other devices are waiting for bus ownership, it may simply grab the bus again and transfer more data.
> 
> ...


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## Ketxxx (Jan 11, 2008)

Thats very strange, 9\10 times reducing PCI latency increases the chance of getting crackling, and effects stability. Must be something to do with how guitar hero was programmed - possibly to reduce sound lag.


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