Please explain to me what is PCI & AGP MHz Locking

[Palmer]

Hi,

Sorry for ignorance, but what is PCI & AGP MHz locking? What is its effect upon the operation of the motherboard?

I am looking to buy either an ASUS A8V or an ABIT AV8.

I read somewhere that the ASUS A8V has 'PCI & AGP MHz Locking'. I have not seen that the ABIT AV8 has this facility.

Would you say that it is of sufficient importance to influence the choice of a motherboard?

Many thanks.

Palmer.

 

[CrispyFried]

Its for overclocking, so you can raise the front side bus (CPU/memory speeds) without effecting the pci/agp bus speeds, otherwise they go up also. AGP tops out around 73 mhz before screwing up and pci at about 38 (?). So by locking them at 66/33 you can do insane overclocks.

If you dont overclock then dont worry about it.

 

[Concillian]

If you are not overclocking, don't worry about it.

If you are overclocking, this is a KEY feature.

AGP and PCI slot frequencies are often tied to another frequency on the motherboard (lower complexity = cheaper). If you overclock, you generally increase one of the frequencies that are directly tied to the PCI and AGP speeds (usually PCI = FSB speed / 6 and AGP = FSB speed / 3).

There is not much margin in PCI and AGP speeds, AND the speed of the slots is a rather un-important parameter when considering the overall speed of the system as a whole.

By 'locking' the PCI/AGP you are really separating these frequencies from others so you can keep the PCI and AGP bus at a nice stable frequency while increasing frequencies of other components (particularly the CPU)

 

[Palmer]

Thank you very much for your clear and comprehensive response.

Palmer.