AGP & PCI Bus speeds

[PG]

I have a Powercolor PVK7, with the via kx133 chipset and AMI bios. My board allows me to change the FSB with jumpers. As you all know when you bump up the FSB you also bump up all the other buses. My question is how do I turn the other buses down? I have looked in the bios and don't see any way to do it. The only jumpers I have are for the FSB. What bus speeds are the AGP and PCI buses stable to?

 

[Megahurtz]

PG (May 17, 2001 04:38 p.m.):
I have a Powercolor PVK7, with the via kx133 chipset and AMI bios. My board allows me to change the FSB with jumpers. As you all know when you bump up the FSB you also bump up all the other buses. My question is how do I turn the other buses down? I have looked in the bios and don't see any way to do it. The only jumpers I have are for the FSB. What bus speeds are the AGP and PCI buses stable to?

You are probably stuck with a fixed divisor for the AGP and PCI buses. Unless that motherboard has adjustable divisors..it's highly unlikely. Consult your manual.

How high you can overclock your PCI and AGP buses is largely dependant on component quality, and to a lesser degree on the ability to raise the 'VIO'. Don't go above 3.6V, as this may shorten your component life quite dramatically. It is all pretty much trial and error.

T

 

[FRANK]

It sounds like you've just stumbled on to one of the challenges of overclocking. On some motherboards you can't change the FSB / PCI ratio manually. At 100 FSB the ratio would be 1/3 yielding a PCI bus speed of 33MHz. As you increase the FSB the PCI bus speed increases as well. On some boards such as the FIC AD11 the ratio changes to 1/4 when the FSB hits 120, meaning a PCI bus of 30MHz, on some others the change takes place at 133. I believe I've seen some motherboards that do have and option in the BIOS to set the ratio manually, I don't know which ones.

This is a good example as to why there are other factors to take into account when overclocking a "system" Some peripherals, such as the video cards and particularly NIC's get a bit flaky as the FSB increases. Many people have invested substantial amounts of time and money, only to have the performance limited by a $9.95 generic network card. This is the reason that it is important to use high quality parts in every part of your "system" as you try to eliminate the weakest link.

Research, the key to a successful overclocking experience!

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