XP-Mobile and locked PCI/AGP dividers

fbomba6fbomba6
edited June 2004 in Hardware
Recently I installed a new motherboard (Aopen AK77-600 Max based on VIA KT600) and the excellent XP-mobile 2400+ processor (AXMH2400FQQ4C). The unlocked multiplier and adjustable vCore are incredibly cool to play with, and CrystalCPUID PowerNow real-time throttling in Windows is really great!

Unfortunately I have some problems with FSB dividers.

Mobo BIOS does not recognize the CPU ("Unknown CPU type") and sets it at 6 x 100, which is common as far as I read in other posts. I can freely set FSB and multipliers, both within BIOS and Windows. My motherboard never changes PCI/AGP dividers that stay locked at 1/3 and 2/3!

In other words, if I try to set 133 Mhz FSB (factory specifications of XP-M 2400+) the PC does not boot because of PCI bus set at 44 Mhz.

On AK77-600 Max there's a "K7 host clock" jumper which has two possibile values: "auto detect" and "100 Mhz". None changes the board behaviour. My BIOS revision is R1.08 and I have two 512 Mb DDR400 RAM modules; the board uses a Cypress W312-02H clock generator.

Do you know of any hack or trick to solve this situation?

Thank you and bye from Italy
FB6

Comments

  • muddocktormuddocktor
    edited June 2004
    Welcome to Short Media, fbomba6.

    I have no experience with that board or any KT600 board, but the only solution to the problem you are having would be to mod the L6 and L3 bridges back to desktop XP standards I think, unfortunately. I've never had that problem but I am using nforce2 boards exclusively for my mobiles and they have an agp/pci lock.

    If you would decide to mods the bridges, you would have to close all the L6 bridges by filling in the laser cut with something like superglue and then carefully scraping the fake pcb covering off the L6 bridges and connecting the bridges with conductive paint. You will also have to mod the L3 bridges by cutting 1 bridge too, so that the L3 bridges look like l : : l after you are finished so that it enables your mobo to see then proc as a desktop XP processor.

    If you do decide to mod the bridges, you could try just cutting the L3 bridge first, which is the mobile sense bridge and see what happens. Your board may then let you select different agp/pci multipliers.

    Sorry I can't be more help though. Why did you decide to go with a KT600 based board if you were planning to overclock this baby, if I may ask? The utter lack of a lock on Via's pci and agp busses on their socket A chipsets has kept me from buying anything from them since the nforce2 came out if I was planning to do some serious fsb overclocking.
  • fbomba6fbomba6
    edited June 2004
    Actually, my aim is not to overclock to the death and rather to have a silent, scalable system. Chipsets made by nVidia are generally regarded as better pieces of hardware but they miss the Powernow management that allows my VIA motherboard to dynamically adapt multipliers and vCore according to system load.

    My desktop system is often more silent than a notebook! Moreover I don't think that the problem is with AGP/PCI lock but with the multipliers themselves. I guess that a simple BIOS patch from Aopen should solve the issue (it's just a recognition thing after all) but at the present time I am stuck at sub-specification performance.

    Bye again
  • fbomba6fbomba6
    edited June 2004
    I'm beginning to think that AOpen BIOS determines the PCI/AGP ratio to use using detected FSB of the processor. In other words if it reads 100 FSB it will fix PCI to 1/3 regardless of what FSB I set (which is correctly applied). If I make the board believe that I have a 166 FSB CPU it will fix the ratio at 1/5.

    Do you know of any pin modding trick or WPCREdit hack just to change detected FSB of XP-M processor?

    Thank you
    FB6
Sign In or Register to comment.