PowerCore / Konnekt / Impact Twin: Optimizing PCI performance

Question

I hear clicking and popping sounds in the audio while the audio is being played back. Sometimes these noises will be continuous, but in other situations the clicking and popping will only occur occasionally. What can I do?

Answer

Please try to optimize the PCI performance by adjusting the PCI Latency Timer setting within BIOS.

The PCI Lateny Timer setting controls how long each PCI device can hold the bus before another takes over. The longer the latency, the longer the PCI device can retain control of the bus before handling it over to another PCI device. Normally, the PCI Latency Timer is set to 32 cycles. This means the active PCI has to complete its transactions within 32 clock cycles and hand it over to the next PCI device.

For better PCI performance, a longer latency should be used. Try increasing it to 64 cycles or even 128 cycles. The optimal value for every system is different. You should benchmark your PCI card's performance after each change to determine the optimal PCI latency time for your system.

Please note that longer PCI  latency isn't necessarily better. A long latency can also reduce performance as the other PCI devices queuing up may be stalled for too long i.e. systems with many PCI  devices or PCi devices that continuously write short bursts of data to the PCI bus. Such systems would work better with shorter PCI latencies as they allow rapid access to the PCI bus.

In addition, some time-critical PCI devices may not agree with a long latency. Such devices require priority access to the PCi bus which may not be possible if the PCI bus is held up by another device for a long period. In such cases it's recommended that you keep the default PCI latency of 32 cycles.


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