This week TechARP discusses the CPU to PCI Post Write BIOS option, you can read about it over here.
This BIOS feature controls the chipset's CPU-to-PCI write buffer. It is used to store PCI writes from the processor before they are written to the PCI bus.
When enabled, all PCI writes from the processor will go directly to the write buffer. This allows the processor to work on something else while the write buffer writes the data to the PCI bus on the next available PCI cycle.
When disabled, the processor bypasses the buffer and writes directly to the PCI bus. This ties up the processor for the entire length of the transaction.
It is recommended that you enable this BIOS feature for better performance.