BIOS is not soldered.

Here's a high resolution image of the MB with 256 KB cache module.

EDIT: This image is probably more appropriately placed with the Ultimate 486 Benchmark Comparison since this was the motherboard use for this project. Refer to this link for the image,
Re: The Ultimate 486 Benchmark Comparison

@feipoa
did you know how to perform "hot-flash" on the M919

the pictures came now!!!

BIOS used to flash M919

1996 BIOS

1996 BIOS "Plug and Play & BootBlock Supported"

Uniflash options not greyed-out

Flashing 1998 BIOS in progress

Almost flashed

Flashed on the M919

1998 m919 BIOS POST

Advanced Setup (1)

Advanced Setup (2)

Advanced Setup (3)

Chipset Setup (1)

Chipset Setup (2)

Chipset Setup (3)

Power MgMt

Peripheral Setup (1)

Peripheral Setup (2)

@feipoa
>In this picture i see "NCR SCSI at AD17 Present In" is this thing the one you wondered?

Setup

Utility

Security

Default

@feipoa
you must change some options in "Peripheral Setup" section for get the Floppy and COM ports working

My M919 default BIOS not flash-able

My M919 case

Fan attached to the IBM 5x86

side view

My M919 mobo

My M919 ram numbers

Full RAM view

@feipoa
by the way, with the attached fan and all isn´t possible OC the IBM 5x86 😠
in this page i found some information:
http://www.cpu-collection.de/?tn=0&l0=cl&l1=5 … yrix#5x86-120GP
some mentions the Cx 5x86-120 can´t overclock

the images are crappy?
you flashed the BIOS?
what are your AT cases?post pictures
my AT cases are here
486 mobo + 586 chip
there are down all

It doesn't look like any user-controllable options have changed in the BIOS, but there may be other fixes. Too bad we don't have a revision history. Thank you for the images.

I have never hot-flashed a BIOS before, but I think this is what I'd do,

METHOD A

1) On M919 motherboard with non-flashable BIOS, partially remove the BIOS so that it is just connected.

2) On M919 motherboard with partially connected non-flashable BIOS, boot the system without a boot disk in place and no harddrives. When the system requests the user to insert a diskette, swap out the M919 BIOS and put in the HOT-433 BIOS, then insert a DOS boot diskette.

3) Run the Uniflash utility and flash the BIOS to the M919 1998 revision.

METHOD B

Is it possible to just flash the HOT-433 BIOS inside the HOT-433 with the M919 1998 BIOS? Once flashed, quickly turn off and move the BIOS to the M919 motherboard?

Which method works? Both?

Btw, I just LOVE that AMI windows BIOS. When I showed it to a friend of mine he was like 😳 😳 😳
He never knew it existed!
Course theres a reason why we use text based BIOS's these days, but it sure seems like the easiest way to test serial mice 😁

@feipoa
i think both of these methods must works,but i make this

1) On M919 motherboard with non-flashable BIOS, partially remove the BIOS so that it is just connected.

2) On M919 motherboard with partially connected non-flashable BIOS,set BIOS to boot from floppy

3)Boot from floppy, run Uniflash, remove the non-flasheable BIOS & insert flash-able BIOS

4)In Uniflash press Redetect Flash ROM

5)Flash the BIOS

@feipoa
You can attach the "DOS Benchmark Pack"? (if possible)
just do not include Sppedsys, 3DBench, DOOM & Quake because i have already them
also you can attach Sandra99?, because i don´t found this benchmark

Well, I flashed into this 9/15/1998 M919 BIOS but have not noticed any fixes with L1 cache of Intel/AMD WB-enabled CPUs, nor fixes with SCSI bus mastering. The only new user-controllable BIOS feature I can find is an option for inputting the address of your NCR SCSI, which is greyed out always, at least for an Adaptec 2940U2W.

I wonder what was fixed? Better yet, I wonder what new bugs PC Chips introduced with this "fix"? Them seem to have removed mouse support in the BIOS, not like anyone really used that feature, but it was a quick way to test mice. I guess I'll check out the 10/10/1996 BIOS.

udam_u wrote:

Thank you feipoa! I wasn't able to find this bios on the internet. Unfortunately bios on my motherboard has this small window. Have you ever removed award sticker from your bios? If so, what is typed on it? Maybe I can find the same part on one of my damaged motherboards... ^^

I guess you can find flashable BIOS on Pentium mobos, and you should make/try a hot flash
HOT-flash instructions:

1) On motherboard with non-flashable BIOS, partially remove the BIOS so that it is just connected.
2) On motherboard with partially connected non-flashable BIOS,set BIOS to boot from floppy
3)Boot from floppy, run Uniflash, remove the non-flasheable BIOS & insert flash-able BIOS
4)In Uniflash press Redetect Flash ROM
5)If it detects the BIOS as flash-able, go on flashing the BIOS!
6)Flash the BIOS

Warnings:
See if it detects the bios as 128k or 256k in the organisation section
If it detects as 128k go on!
If it detects as 256k you had to make a few steps before flashing:
1-Copy the file uud0520s.bin (supplied by feipoa) to a floppy
2-Boot using a boot disk
3-remove the boot disk and insert the flash floppy
4-type in the command
copy /b uud0520s.bin+uud0520s.bin bios256.bin
This way, the 128kb BIOS can be programmed into the 256kb chip.
5-flash as normal

Special note:
Don't remove the BIOS with metal tools/screwdriver or things may get wrong with your mobo

retro games 100 wrote:

I understand from reading old posts on Vogons that a good VLB board is better than most (if not all) PCI boards, in terms of video performance. I am beginning to doubt this notion, having seen my PCI Biostar score 12.5 on Pcpbench (default mode) with a Virge 325, and also having got this system stable at 200 MHz within Windows 98.

Was that the Ultimate non-Cyrix/POD 486 score for PCPbench, 12.5?

50MHz CPU clock x4, 33MHz PCI/memory, 3/2 divider?

That is a very, very cute result! 😀

Does this motherbord works at 66Mhz FSB? I mean stable?
How much RAM it handling - max?

Nice necropost.

If you read Feipoas utlimate 486 thread, he has a pretty good writeup on this board.

In short, 66MHz appears to be stable, at least on his revision. He's been running at 66MHz for years and it still works.
The maximum RAM is 256MB. Feipoa's board has been modified to accept 1024kb cache so he can cache all of it too.

therelaxer wrote on 2011-01-26, 16:58:

Is there a way to calculate the cacheable limit for the L2 cache on this motherboard? I have 256k with a 32K x 8 TAG and 4 x 32K x 8 in bank 0 and 1.

The cachable limit is(not using log())...
(2nd_lvl_cache_size_in_KiB * 2^tag_bits) / 2^dirty_bit
(256KiB * 2 ^ 8 ) / 2^writeback_enabled = 64MiB / 2 = 32 MiB.
This is why a larger 2nd level cache enables more cacheable ram(indirectly requiring a larger tag also).
The sram tag size(8,16,32,64,128) is only interesting for the slots in the cache - since one cache line on the 486 is 16 bytes, a common 256KiB cache only needs a tag of size 256KiB / 16 = 16KiB(despite what the manuals often say - albeit there can be strict requirements preventing the board from booting). The more adress bits the more "reach" but the more "stretched out" the cache.
A big 2MB cache would require a 2MiB / 16byte = 128KiB tag(2 x 64Kib if seperated into two banks).

Anonymous Coward wrote on 2020-06-30, 08:14:

Nice necropost. […]
Show full quote

Nice necropost.

If you read Feipoas utlimate 486 thread, he has a pretty good writeup on this board.

In short, 66MHz appears to be stable, at least on his revision. He's been running at 66MHz for years and it still works.
The maximum RAM is 256MB. Feipoa's board has been modified to accept 1024kb cache so he can cache all of it too.

Thanks. I'd like to buy it. 256 MB means 4*64MB EDO RAM. I would like to 512 MB on this old chipset of UMC.
What about new layout this motherbord with some memory mappers? It could help handling much more RAM and cache memory up to 2MB. Only wright BIOS to flash remaining.

Tymo486DX2 wrote on 2020-06-30, 16:40:

Thanks. I'd like to buy it. 256 MB means 4*64MB EDO RAM. I would like to 512 MB on this old chipset of UMC.
What about new layout this motherbord with some memory mappers? It could help handling much more RAM and cache memory up to 2MB. Only wright BIOS to flash remaining.

This won't work.
There are 128 MB modules, but when you insert these modules you have to leave the neighbour bank blank.
It is a limitation to the UMC chipset. Neither it supports more than 1024 KB cache.
So you can put 128 MB modules in slot 1 and slot 3. Slot 2 and slot 4 have to be empty.

However, you have a big performance penalty when you do not have enough cache. Remember to get the whole DRAM cacheable, you need 1024 KB cache for 256 MB in write through mode. In write back mode, 1024 KB cache cover just 128 MB DRAM.

Thanks a lot again.
Does exist wright another chipset of UMC with all demand features anyway?

I mean other motherbord?

I have had about 15 years Intel Pentium II MMX at 233MHz on Microstar MS6119 and Intel 440BX chipset.
All the time I have been used FSB 66MHz. Motherbord had 3 memory banks for 256 MB each one.
All together max RAM handling 768 MB.
Theres the different beetwen 256 MB of UMC chipset and 440BX of Intel. I am still searching wright chipset.
FSB 66MHz
2MB cache, 512 max RAM, 4*memory banks 72pin, EIDE 2* controller.

Tymo486DX2 wrote on 2020-07-01, 01:57:

Thanks a lot again. Does exist wright another chipset of UMC with all demand features anyway? […]
Show full quote

Thanks a lot again.
Does exist wright another chipset of UMC with all demand features anyway?

I mean other motherbord?

I have had about 15 years Intel Pentium II MMX at 233MHz on Microstar MS6119 and Intel 440BX chipset.
All the time I have been used FSB 66MHz. Motherbord had 3 memory banks for 256 MB each one.
All together max RAM handling 768 MB.
Theres the different beetwen 256 MB of UMC chipset and 440BX of Intel. I am still searching wright chipset.
FSB 66MHz
2MB cache, 512 max RAM, 4*memory banks 72pin, EIDE 2* controller.

May I ask why you are looking for this very particular chipsetted board? Why UMC?

Of course!
I want to assembly ancient art computer.

I have choosed UMC best possible brand ever. Simply I am fan.

Probably that chipset of UMC does exists...

Tymo486DX2 wrote on 2020-07-01, 01:57:

Thanks a lot again. Does exist wright another chipset of UMC with all demand features anyway? […]
Show full quote

Thanks a lot again.
Does exist wright another chipset of UMC with all demand features anyway?

I mean other motherbord?

I have had about 15 years Intel Pentium II MMX at 233MHz on Microstar MS6119 and Intel 440BX chipset.
All the time I have been used FSB 66MHz. Motherbord had 3 memory banks for 256 MB each one.
All together max RAM handling 768 MB.
Theres the different beetwen 256 MB of UMC chipset and 440BX of Intel. I am still searching wright chipset.
FSB 66MHz
2MB cache, 512 max RAM, 4*memory banks 72pin, EIDE 2* controller.

You have to understand the importance of tag ram width. I haven't seen a 486 supporting tag rams wider than 7+1=8 bits. If your tag ram is not wide enough you just need more cache to cover the whole DRAM (or a wider bus, like 64 bits on Pentium).
That's no wonder because the L2 of a P2 is on the module. afaik the L2 cache controller and the tag ram is integrated in the CPU die and runs at half clock. For tag ram width, adding some thousands of transistors and a few conducting lines internally on a cpu die is much less effort than adding extra pins/lands for the chips and tracing them on a PCB.