abasak wrote on 2022-12-26, 21:03:

I have a Celeron 300A on a slotket adapter (ms6905 ver 1.1) in a FIC KA-6100 board. The slotket is set to auto voltage. However no matter whatever I do, the CPU overrides the multiplier settings making it impossible to do anything but 4.5 x of whatever bus speed I set and sadly 4,5 x 100Mhz crashes the machine.

Have you guys ever experienced that?

Btw. I have tried setting the slotket jumper to opened and closed that does the "B21" trick, but as I remember that was a Mhz-thing not a multiplier thing.

Yes, most CPUs are multiplier locked, partly or completely and have been for decades. the 300A is locked to 4.5x .

Ah okay, thanks. I just thought I could change it since the slot 1 board lets me set the multiplier.

Having the CPU multiplier settings on the motherboard doesn't guarantee that it works with all CPUs. In my case it only worked on a PII-400 that has the multiplier unlocked downward.

abasak wrote on 2022-12-26, 21:03:

Btw. I have tried setting the slotket jumper to opened and closed that does the "B21" trick, but as I remember that was a Mhz-thing not a multiplier thing.

The B21 trick is to allow the use of 100 MHz FSB on Celeron CPUs for overclocking (Mendocino Celerons are very good at this given the on-die L2 cache 😉). Try setting a manual core voltage setting instead of "Auto" on the slotket.

How much would you set the voltage to? 2.00?

Another thing that is an issue is, whenever I set the FSB to 100 Mhz the motherboard seems very picky about which video card it will work with. Geforce 4 MX440s kinda works but crashes in hires mode in Hi-Octane. My Matrox G550 doesn't even post. My 3DFX Banshee hangs when the system is detecting IDE drives, and as I recall my AGP Radeon 7000 did the same thing. PCI cards wouldn't even display an image even when I set it to initialize the PCI slot first.

I would set it around 2.0v-2.2v.

Strange thing about the video cards being picky considering that the VIA chipset the motherboard has officially supports 100 MHz FSB. Then again, non-Intel chipsets are quite a gamble to get them working reliably.

Thanks.

What makes this extra strange is, that the motherboard actually supports up to 133mhz FSB.

Sounds like I should try to get a different board then, sucks that they are so pricy now.

EDIT: Do you know of any BIOS settings that could make it more stable at 100Mhz

Okay, how about a deep dive into this problem?

Does anyone have both locked and unlocked examples of a same model (core/package) socket 370 cpu?

Maybe some probing around with a colt meter could be done?

I know it’s probably a fools errand and was probably done in gold wire or on die, but can’t hurt to give it another go with fresh eyes

Thanks for your reply. That would be pretty interesting. I only have this model.

However after having changed the voltage to 2.1v nothing really seemed to happen, BUT when I took out one of the RAM sticks it behaved fine. So I guess this board is very difficult, because it can only see 128mb per stick (even if it reports it at 131mb) no matter if it is a 128mb, 256mb or 512mb stick. If I put in 2x128mb sticks I can get it to see 261mb of RAM (strange amount), but the system is unreliable and hangs in my hires Hioctane test.

I am running PC133 RAM.

It works okay at FSB at 75Mhz with two sticks of RAM.

abasak wrote on 2022-12-26, 22:19:

EDIT: Do you know of any BIOS settings that could make it more stable at 100Mhz

For that motherboard, sadly no. 🙁

At least I'm glad that you got it somewhat working at 75 MHz FSB.

afaik early p2s were unlocked, but it was unlocked downwards. there was a minimum multi for l2 cache to be active. pii 350 was the 1st multi lock but there is a version of 350 that is not. the version thats locked is the ones that came out the week the p400s came out. they were maybe down binned 400s i guess. so after august 1998 all cpus were locked, anything before that depends.

https://www.ocinside.de/workshop_en/change_intel_multi/

B21 pin
http://www.thg.ru/cpu/19980514/print.html

Please check AGP multiplier, if it is set to 1:1 then you will have problems with video cards even at 100 mhz. It can be jumper somewhere on the board or BIOS setting.

Thanks for the suggestions and help.