The +33 and -33 options for the VIA133a Chipset

[Siamese]

I heard somewhere that this only works when your FSB is either set at 66, 100, or 133.

I've also heard that if the FSB isnt at one of the standards above it drops the interval by what your pci bus is so lets say im at 146mhz fsb and the pci bus is at 36.5mhz, if I use the -33mhz bus, my fsb will drop to 109.5mhz

So does anyone know what the real deal is?

[Maxout]

As far as I know, it is only the speed of the RAM that is affected. So that if your running high FSB and your RAM won't cut it, you can scale back it's speed so the system will work. I think it was designed as a fix for cheap PC 100 to run with EB Processors.

[Rick25]

It's designed to help you get the most out of your memory. Only the memory transfer speed in affected, the FSB stays at whatever you set it. I'm running a 366 on a 100FSB but since I've got PC133 memory I have an option. I set the divider to 3/4 and it ups my memory speed to 133, nice improvement in bandwith.

[Dimarini]

It is only + or - 33 Mhz at 66, 100 or 133. It is actually the FSB speed + or - the PCI speed.

Usually at speeds above 124Mhz you will only have an option for FSB-PCI speed.

You are correct at 146 FSB your ram could run at 146 or 109.5 Mhz.


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Mike
http://www.monster-machines.com

[Siamese]

Thanks Dimarini. Maybe I can hit 160 with this option then, ill update u all