BIOS Updates forum

On two different systems, I'm running dual PIII 650Mhz (6.5x100Mhz) processors in a Tekram P6B40D-A5 Motherboard, with a BIOS that NickS patched for me to support > 137GB hard drives and all works great.. I'd like to up the FSB to 124 or 133Mhz, and I think my memory and AGP cards will handle it, but I know my PCI cards won't. The BIOS doesn't have a way to change the FSB / PCICLK divider, so I'm pretty sure it's at 2/3, which means my PCI bus is running at 44MHZ or so...

Does anyone know what it would take to patch a BIOS to set the PCICLK to 2/4 (1/2) of the FSB clock? I know some later 440BX boards had this ability. TEKRAM hasn't released an update to this BIOS for a long time, so getting any help from them is unlikely..

If I can get this resolved, I should be able to upgrade to Dual PIII-S Tualatins at 1.4Ghz without having to replace the motherboards.

BIOS String - 02/18/2000-i440BX-W83977-2A69KTG9C-00

Thanks very much.

The CPU clock to PCI ratio is determined by settings in the clock generator chip. Which clock generator chip do you have ?

I seem to remember that there are some utilities around along the lines of PowerTweak which may allow you to play with the settings.

Powertweak doesn't seem to do anything for me...

How do I tell which clock generator the board has? What do I look for?

Looks something like this: although the number of pins may vary. Usually very close to the small metal lump which is the crystal oscillator.
Typically ICS or IDT, you can just make out "ICS" on the pic above.

The clock chip is a W48S101-04H. I can't find any information about it on the IC Works / Cypress website.

SoftFSB and CPUCool support it. I've submitted a request to Cypress for the PDF which used to be at ICWorks but which Web Archive didn't archive.

Thanks.. Let me know if you find out anything...

Datasheet received....Pins select 66 or 100 MHz, software can set 66.8, 68.5, 75, 83.3, 100, 103, 112 or 133.3 MHz, but the PCI ratio is fixed depending on frequency, depressingly. So you're stuck with
133.3 - 44.43 MHz PCI.
112 - 37.33
103 - 34.33
100 - 33.33
83.3 - 41.66
75.0 - 37.5
68.5 - 34.25
66.8 - 33.4

Damn.. I was afraid of that.. No way my PCI devices will run at 43.33 Mhz.. AGP works fine, but not the IDE controllers.

Oh well.. Thanks for the effort and for the info.

Tom

Try a PCI UDMA controller - some of them should work evnen with high PCI clock
I had a Promise Ultra 33 running on a 486 Board with 40MHz PCI - no problems with it

Actually, that's exactly what's hanging up. The on-board IDE seems to work just fine (initializes, detects the DVD drive), but the Promise Ultra 100 board doesn't do a thing. I might play around with the slot positions and see what that does, but I'm not hopeful.

I'm thinking about scrapping the whole thing and building a dual 2400+ Athlon system. I'm using this as a Home Theater PC which requires a lot of horsepower to be able to encode a live video stream in real-time, especially with some of the higher quality encoders.

Thanks...

You would have thought by this time some manufacturer would be making a replacement chip that would lock the bus clocks at their proper frequencies...and make them synchronus, or asynchonus, depending on what your motherboard would require. The market would probably not be very big for this though...

Either that, or some hobbyist would design a daughterboard circuit to do this that could be adapted to fit a motherboard...especially for the older boards that could benefit from an increased CPU clock (ie: Socket 7 with 100MHz CPU clock for an AMD K6-2/III+, with synchronus bus clocks)...

Tom's Hardware has a review of the Powerleap adapter which does this allowing you to run 1.4 GHz Celeron in a Slot 1 mobo.
http://www.tomshardware.com/cpu/20030107/slot_1-01.html Also described at http://www.powerleap.com. I usually find by the time you've paid for the adapter you're half way towards buying a new board, but it may be affordable in the USA.