Using Horun's RTC with AIC-7880 pre-disabled allowed me to floppy boot and reflash the BIOS to the original v14. I'm still shocked that this board doesn't have a recovery mode or a jumper-able means to disable the embedded controllers.

I'm going to reinstall my motherboard to the chassis this evening then its back to square 1. The benefit we have now is knowing that the boot ROM enable feature is hidden in the Security tab of the BIOS. I assume the natural next step is to load the Adaptec-supplied 2940UW BIOS onto an NIC with boot rom enabled?

Good to know you were able to flash it back. Yes is odd that no SCSi disable jumpers exist. I have 3 other motherboards with built-in Adaptec scsi and all 3 have a scsi disable jumper. Maybe it was purposely left off like the IDE header...

I'm glad to hear you got your system back up and running!!

Got the Dallas DS1585s today, waiting on the micro pcb and crystals. Estimated cost to remake a DS1587 is about $13 each which is very reasonable considering how rare they are.
Will post a parts list and simple layout when everything comes together.

Where are the PCB’s coming from?

feipoa wrote on 2020-02-06, 22:39:

Where are the PCB’s coming from?

www.microcontrollershop.com is where I ordered the PCB. They have nearly exact what I was looking for and for reasonable price (about $2+ each). My DS1585c are SOIC so need a SOIC to 28pin DIP pcb, the Xtal is 32.768Khz 6pf (not 12pf standard load) so had to order them as did not have any. Got them thru digikey for cheap. Only thing did not order was the vertical coin battery holders, have a few but not sure if they will work until PCB arrives (can always use a ext bat pack with STD 4 pin connector). I made a top view image

Update on progress with this system:

1) Horun will be sending me some of those DS1585 chips to experiment with.
2) Haven't gotten around to trying the Adaptec BIOS on the NIC card yet.
3) Have been installing the software on my 3 OSes - NT4 (4 GB), Win98SE (4 GB), W2K (26 GB). I like to install all the software on my system that would have been used towards the end of its life, like Office 97, Acrobat distiller, Photoshop 4/5, etc. I've finished the NT4 software setup. Seems that not many games work on it, but there was a common theme - the games all let you install but don't tell you until its time to play that they won't work on NT4.

4) I'm trying to install games on Win98SE but am noticing that 4 GB is not nearly enough. Having proper int13 translations would have fixed this, but I'm not having much hope there. I was thinking of some options for that: a) use partition magic to shrink the w2k partition down to 11 GB and make a 15 GB FAT32 partition for Win98 Games; b) convert w2k to FAT32 so that Win98SE can read/write to a folder on there called w98games, but I find using FAT32 on W2K a bit blasphemous, thus; c) install a program/driver for win98 that lets you read/write to the w2k NTFS partition in folder w98games. There was a program from winternals that would allow for this, it was called NTFSWindows98 and was freeware for read-only. Its located here: http://clients.askew.net/sysinternals/Files/?C=S;O=A If you wanted write do the NTFS partition, you had to pay the $59 for the upgraded version. There was a similar program for NT4 allowing the OS to read/write FAT32 partitions and it works great. Unfortunately, I have been unable to locate the full version of NTFSWindows98. Another outfit made a similar program and it was called Paragon NTFS for Windows 98. It had a trial version, but I have been unable to locate it. I'm not sure if the trial version was read-only as well, or if it was read/write for a limited period of time. Nonetheless, it seems that Microsoft did a good job at ridding the internet of these programs. They really didn't want people adding useful features to their older operating systems and kept pushing new OSes on the users.

5) I ran Tweak BIOS to see which BIOS adjustments could be made to speed up the system. Default view is here:

I tried the following adjustments which according to Tweak BIOS are optimal:

But either they made the system crash or they offered no speed improvements in cachechk, DOOM, and Quake.

6) The fan on my GF2 MX400 non-standard and has been making a ruckus, so I might replace it with a Radeon 7000 once I've finished installing software for the 3 OSes.

7) Ideally, I'd like to upgrade the CPUs to P233 MMX, but there hasn't been much by way of socket 5 upgrade interposers showing up for sale. I have one from Kingston and one from Evergreen, but don't like the idea of using two different upgrades on the same motherboard.

8) The Advance Sound ALS100 sound card I'm using in the system seems to have issues whereby sound doesn't play when playing DOS games from within Windows 98se. I just hear this echoing sound after trying to fire the gun in DOOM. Not sure if this was a common issue and if there is a simple solution.

When using a split-rail VRM interposer, I am pleased to report that a AMD K6-III-450AFX chip will function properly on this motherboard at 400 MHz. I tried a K6-2+ chip, but the screen stayed blank, so perhaps only the non-plus chips work. I am also pleased to report that my Pentium 266 MMX Tillamook chip also functions properly with L2 cache enabled. Seems like very few socket 5/7 boards run properly with a Tillamook (SL2Z4), but this one does. Tested it in DOS and Windows with a few games. Note that the ADS# and ADSC# pins need to be bridged on the the SL2Z4, which can be done on the top surface. I also have the 4x pins bridged (pins from grid W33 & W34), but not sure if those were necessary.

As for using the w2k partition to store Windows 98SE games, it seems that Paragon made their full version of NTFS for Windows 98 freeware at some point. I believe this download has the read/write access, https://www.softpedia.com/get/System/Hard-Dis … for-Win98.shtml

feipoa wrote on 2020-02-21, 09:14:

When using a split-rail VRM interposer, I am pleased to report that a AMD K6-III-450AFX chip will function properly on this motherboard at 400 MHz. I tried a K6-2+ chip, but the screen stayed blank, so perhaps only the non-plus chips work. I am also pleased to report that my Pentium 266 MMX Tillamook chip also functions properly with L2 cache enabled. Seems like very few socket 5/7 boards run properly with a Tillamook (SL2Z4), but this one does. Tested it in DOS and Windows with a few games. Note that the ADS# and ADSC# pins need to be bridged on the the SL2Z4, which can be done on the top surface. I also have the 4x pins bridged (pins from grid W33 & W34), but not sure if those were necessary.
P266HX.png

As for using the w2k partition to store Windows 98SE games, it seems that Paragon made their full version of NTFS for Windows 98 freeware at some point. I believe this download has the read/write access, https://www.softpedia.com/get/System/Hard-Dis … for-Win98.shtml

Seems like the first time, I've heard of a succesfull Tillamook running .. But I guess that dual only works with P54's?

H3nrik V! wrote on 2020-02-21, 09:24:

Seems like the first time, I've heard of a succesfull Tillamook running ..

Seems like I recall one other user on this forum getting a Tillamook and L2 working on a socket 5/7. I forget which motherboard it was. Of all the socket 5/7 boards I have, I think only one would even boot with the Tillamook, but it had some issue. I was extremely surprised when the Proserva system worked flawlessly with a Tillamook. These are the bridges I have on my Tillamook:

H3nrik V! wrote on 2020-02-21, 09:24:

But I guess that dual only works with P54's?

Not quite. You can run dual P55C's. Unfortunately, I don't have matching socket 5 upgrade modules; never figured I'd need them. But I am able to run dual P55C chips, the P233 MMX, on the Proserva using one Evergreen and one Kingston upgrade module. Evidence:

I've done some early benchmarking consisting of Quake 2 in NT4 and W98SE. At 1024x768x16, I get 32.9 fps in w98 and 37.3 fps in NT4. The part which surprised me was that using the same graphics card, driver, and operating system (w98) the Pentium Pro 512K at 233 MHz scores 47.7 fps. Why is there such a large jump from 32.9 fps to 47.7 fps? Was the on-chip L2 cache that impressive? I figured the MMX instructions would help the P55C, but perhaps not in Quake 2?

feipoa wrote on 2020-02-22, 11:30:

I figured the MMX instructions would help the P55C, but perhaps not in Quake 2?

MMX on the P55C has a huge drawback: you could *either* use MMX or the FPU, but not both. This was fixed with the PII. Since Quake 2 uses the FPU heavily, it can't use MMX, so no advantage here for the P55C. The faster L2 cache of the PPro does the rest.

ps: your P55C system seems to completely lack L2 cache..?

derSammler wrote on 2020-02-22, 11:40:

ps: your P55C system seems to completely lack L2 cache..?

I have same system and it does have L2 cache. 256k on board plus a 256k COAST. Due to the cache being shared between cpu's some utils do not show it properly.

feipoa wrote on 2020-02-22, 11:30:

The part which surprised me was that using the same graphics card, driver, and operating system (w98) the Pentium Pro 512K at 233 MHz scores 47.7 fps. Why is there such a large jump from 32.9 fps to 47.7 fps? Was the on-chip L2 cache that impressive?

Yes the P.Pro (P6) was a big improvement over P5 at same cpu speeds.

Its interesting how much more efficient NT4 is with the dual CPUs then Win98
8-9% improvement just by the OS change is pretty impressive.

I do have more of these systems if others want to play 😀
Be fun to see one running a 3dfx card

Windows 98 isn't making use of the second cpu just NT4 is.

derSammler wrote on 2020-02-22, 11:40:

ps: your P55C system seems to completely lack L2 cache..?

It was common for system utilities to incorrectly detect L2 cache on older systems like this, particularly when using NT4. I also ran Sandra99 in Windows98SE, and it reports 512 KB of L1 pipeline burst write-back cache, while Everest reports 0. The Speedsys screenshot from running the Tillamook shows 512K L2 cache as well.

cpushack wrote on 2020-02-22, 19:06:

Its interesting how much more efficient NT4 is with the dual CPUs then Win98
8-9% improvement just by the OS change is pretty impressive.

Could be that the second CPU in NT4 is taking care of some background tasks. Unfortunately, very few games run in NT4. Half-Life works though.

Another thought I had about the Win98 vs. NT4 speed differences was: could running Quake2 in Win98SE from an NTFS partition be slowing it down? Not sure what kind of overhead there is involved with the Paragon NTFS for Windws98 driver.

cpushack wrote on 2020-02-22, 19:06:

Be fun to see one running a 3dfx card

Yeah, the system would fly with a 3dfx card. Unfortunately all my 3dfx cards are in systems now. I have found it very difficult to keep 3dfx cards in the drawer!

feipoa wrote on 2020-02-19, 06:37:

Update on progress with this system:

1) Horun will be sending me some of those DS1585 chips to experiment with.

Shit yes I need to mail them. And need to email cpu-shack about a cpu purchase we chatted about like a month ago 🙁
time flies when your not having fun 🤣
Screwed up my Win2k install trying diff sound cards, halts during startup with an error. Win98se runs fine on this system after many hardware changes !

Hopefully you hadn't yet installed the 200+ individual post-SP4 updates manually. When I'm finished with setting up w98 games, I'm going to see if the trick to get w2K auto updates going still works.

So very cool, running dual p55's!

H3nrik V! wrote on 2020-02-23, 06:05:

So very cool, running dual p55's!

...but with very non-matching interposers, fans, and heatsinks :(

feipoa wrote on 2020-02-23, 13:07:

H3nrik V! wrote on 2020-02-23, 06:05:

So very cool, running dual p55's!

...but with very non-matching interposers, fans, and heatsinks 🙁

But .. DUAL P55'S, damnit!!! Has there ever been ANY "official" board for that?