PCI#2 Access #1 Retry
Common Options : Enabled, Disabled
Quick Review
This BIOS feature is linked to CPU to PCI Write Buffer. Therefore, if the write buffer is disabled, this BIOS feature will not have any effect. However, the reverse is not true. The CPU to PCI Write Buffer feature will still work even if PCI#2 Access #1 Retry is disabled.
When the buffer is enabled, the processor writes directly to the buffer, instead of the PCI bus. The buffer then attempts to write the data to the PCI bus by Passive Release. This allows the processor to perform other tasks without waiting for its data to be written to the PCI bus.
However, the attempted buffer write to the PCI bus may fail because the PCI bus may still be occupied by another device. When that happens, this BIOS feature determines if the buffer write should be reattempted or sent back for arbitration.
If this BIOS feature is enabled, the buffer will attempt to write to the PCI bus until it is successful.
If this BIOS feature is disabled, the buffer will flush its contents and register the transaction as failed. The processor will now have to write again to the write buffer.
Generally, it is recommended that you enable this feature as this improves the processor's performance.
However, if you have many PCI devices and their performance is more important, you may want to disable this feature. This prevents excessive generation of retries by the write buffer which may severely tax the PCI bus. Disabling this feature will improve the PCI bus' performance, especially with slow PCI devices that hog the bus for long periods of time at a stretch.
Please note again that this BIOS feature will have no effect if you disable the CPU to PCI Write Buffer.
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