In Reply to: Re: FSB up USB down? posted by Jeff Roberts on 05/24/02 at 12:20 AM:
One of the problems of overclocking is: What happens with the PCI bus?
FSB and PCI are couples. If you change the FSB, you automaticaly change the PCI bus. With an FSB of 133MHz, the PCI works with 33MHz ( what is the spec. of PCI ). Using FSB 136MHz results to 34MHz PCI, this is out of spec. Some PCI (the USB is a PCI device) devices don't care and work properly (like the USB in your case). With FSB 137 you overclock the PCI bus to 34,25MHz and your USB says: "Not with me".
Changing the core voltage didn't help. It's only needed to get the cpu work properly, during overclocking.
: Overclocking has limitations. You no know the limitaions of your motherboard. There is no fix. If it won't run at 137...don't do that.
: Jeff Roberts
: : XP, DVD266u-RN, Via chipset, Overclocking dual PIII
: : 1.13ghz w/ 512k. All is fine at 136FSB but at 137 USB devices malfunction or become unrecognized. I have tried voltages from 1.45 to 1.6. Any ideas?