Master Priority Rotation from The Tech ARP BIOS Guide!

Master Priority Rotation

Common Options : 1 PCI, 2 PCI, 3 PCI

 

Quick Review of Master Priority Rotation

The Master Priority Rotation BIOS feature controls the priority of the processor’s accesses to the PCI bus.

If you choose 1 PCI, the processor will always be granted access right after the current PCI bus master completes its transaction, irrespective of how many other PCI bus masters are on the queue.

If you choose 2 PCI, the processor will always be granted access right after the second PCI bus master on the queue completes its transaction.

If you choose 3 PCI, the processor will always be granted access right after the third PCI bus master on the queue completes its transaction.

Master Priority Rotation from The Tech ARP BIOS Guide!

But no matter what you choose, the processor is guaranteed access to the PCI bus after a certain number of PCI bus master grants.

It doesn’t matter if there are numerous PCI bus masters on the queue or when the processor requests access to the PCI bus. The processor will always be granted access after one PCI bus master transaction (1 PCI), two transactions (2 PCI) or three transactions (3 PCI).

For better overall performance, it is recommended that you select the 1 PCI option as this allows the processor to access the PCI bus with minimal delay.

However, if you wish to improve the performance of your PCI devices, you can try the 2 PCI or 3 PCI options. They ensure that your PCI cards will receive greater PCI bus priority.

Details of Master Priority Rotation

The Master Priority Rotation BIOS feature controls the priority of the processor’s accesses to the PCI bus.

If you choose 1 PCI, the processor will always be granted access right after the current PCI bus master completes its transaction, irrespective of how many other PCI bus masters are on the queue. This improves processor-to-PCI performance, at the expense of other PCI transactions.

If you choose 2 PCI, the processor will always be granted access right after the second PCI bus master on the queue completes its transaction. This means the processor has to wait for just two PCI bus masters to complete their transactions on the PCI bus before it can gain access to the PCI bus itself. This means slightly poorer processor-to-PCI performance but PCI bus masters will enjoy slightly better performance.

If you choose 3 PCI, the processor will always be granted access right after the third PCI bus master on the queue completes its transaction. This means the processor has to wait for three PCI bus masters to complete their transactions on the PCI bus before it can gain access to the PCI bus itself. This means poorer processor-to-PCI performance but PCI bus masters will enjoy better performance.

General Computer System Diagram - CPU, PCI Express, RAM, North Bridge, South Bridge, PCIe, HDD, South Bridge, PCI. USB, Keyboard, Mouse

But no matter what you choose, the processor is guaranteed access to the PCI bus after a certain number of PCI bus master grants.

It doesn’t matter if there are numerous PCI bus masters on the queue or when the processor requests access to the PCI bus. The processor will always be granted access after one PCI bus master transaction (1 PCI), two transactions (2 PCI) or three transactions (3 PCI).

For better overall performance, it is recommended that you select the 1 PCI option as this allows the processor to access the PCI bus with minimal delay.

However, if you wish to improve the performance of your PCI devices, you can try the 2 PCI or 3 PCI options. They ensure that your PCI cards will receive greater PCI bus priority.

 

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