Paul_V wrote on 2023-03-08, 20:05:

3) CPU bus speed can be run at 100mhz or 133mhz via pin mod. I'm currently running Pentium M 750 1.86 (133x14) at 1.40Ghz(100x14)
4) Adjustable CPU multiplier - x6,x8,x9,x10,x11,x12,x13,x14 (some other Pentium M series may also have up to x21 multiplier)

Btw for the record for people like me wondering what multipliers are supported (not sure if multiplier support is a mobo feature or not), at least x17 does work.

My board came with 1.3 GHz Celeron so upgraded it to Pentium-M 735 (x17) and it just works. Mine had reasonable amount of thermal paste applied from the factory, so i guess it depends on person who puts it together 😀 Changing CPU was a pain like said earlier in this thread as there is no heat spreader and I am no stranger to ruin CPUs by chipping chunks out of the core by misaligned heatsink (those old AMD Duron etc. CPUs).

Pentium-M 735 was easy and cheap to buy, anything above (745 -> x18, 755 -> x20 -> 765 -> x21) and price will jump considerably...

jarp wrote on 2025-06-11, 05:42:

(not sure if multiplier support is a mobo feature or not), at least x17 does work.

It is CPU dependant.
For example, 1.6Ghz Dothan Pentium-M 725 will not have x17 multiplier (100mhz x 16)
The lowest multiplier I tested was x6.

There is a jumper to set FSB bus speed to match 100Mhz or 133Mhz Pentium models.
Or it can be used to overclock\downlcock.

jarp wrote on 2025-05-20, 08:24:

More info about SATA, it works beautifully and (English) manual is misleading. You can plug only SATA drive to the mobo without CF or any IDE drive and it still shows up as primary slave. I have no idea how it is possible to have slave drive without master drive but it works (I guess JM20330 does some magic here which normally would be master drives responsibility), boots and is fast ~75 MB/s (UDMA1000) with my old 120GB SSD. It also works together with CF card and also IDE to mSATA adapter and mSATA drive.

For the record... not sure if it is my old SSD or motherboard but UDMA in general will cause quite a lot of I/O errors and even lockups when using SATA port on this motherboard. So I really had to disable UDMA for SATA drive.

But what is more interesting that I found out there is software way Re: UDMA 5 with DOM's & CF's to cheat chipset to think 80 conductor cable exist even if it does not, even for 44-pin IDE port even though there is no such thing as 80-conductor cable for it. So I have 44-pin to mSATA adapter connected to it with very short cable, like DOM and am able to enable UDMA/100 mode for it and unlike SATA, it seems to be stable and does not cause I/O errors (YMMV though). Speeds I get is the same ~75 MB/s than with SATA drive, but stable...

jarp wrote on 2025-05-23, 20:19:

I was able to aquire Voodoo 3 3000 PCI today and it seems to work just fine! I did not measure if voltages do sag and dc converters struggle but at least everything seems to work no problem...

Also, I was now able to snatch PNY Nvidia NVS280 PCI... Aaaaaand it works. I wonder why, as it is so similar to FX5500? Half the bits for memory bus and only 64MB memory, but other than that, it is the same...?

Now I am battling myself between keeping Voodoo 3 or selling it. I kind of hate prices of 3dfx cards as they are becoming collectors items and using them as daily driver is not economically sane anymore. NVS280 does not suffer the same problem and allows also me to play UT2004 etc.

Cannot resist sneaking in picture of my I(S)A855 setup as my custom 3D printed case for it threatening most Mini-ITX setups is 99% ready (yes, those are low profile cards, finding low profile ES1868 ISA card was... expensive):

Great job. That's one clean setup for sure. Surely, a lot of effort has been put.

Concerning FX5500, my guess at this point is that there may be BIOS issue (including IT8888 resource allocation)
I have tested a motherboard, which use exactly same chipsets, runs AMI BIOS, but lacks IT8888 - FX5500 works perfectly fine.

So, I've ruled out power and chipset compatibility issues for the time being.

But, I have not found suitable replacement BIOS yet.
Some trick in the coding has been used to initialise the integrated memory of ISA855.
All other BIOSes fail at memory init, beause they expect a separate memory module with SPD chip.

There seems to be an ITX version of the board without IT8888 and ISA slots, but I could not aquire one for testing.

UPD
My SPD prototype PCB has finally arrived.
I can confirm, that ISA855 has SMBUS signals routed to PCI slots.
So, I decided to make an addon card for SPD chip, thus eliminating the need to solder it directly to the morherboard.
I've been trying to find another compatible BIOS, preferable AMI, but they all failed at memory config init (E3 POST or similar).
With addon card loaded with SPD rom dump from 512mb samsung so-dimm ddr333, AMI now passes E3 POST, but freezes at 2A.
I'll need some time to double check memory topology on this board.