And when I'd told that it's a gamble, I made an understatement.

Before buying, I specifically inquired available options and specs and was told that the CPUs do come pre-soldered.
While the seller was honest and sent me exactly the Pentium-M variant, it did not come in a BGA package, which is a nice bonus.

Can never use too much TIM, right? 😜

I quite like that it can be powered from a single 12V input, and that it has LVDS - some interesting embedded enclosure designs would be possible.
DOS iMac anyone? 😉

Tetrium wrote on 2022-07-31, 07:56:

Can never use too much TIM, right? 😜

Yeah, I've removed excess paste after the inspection 😀 Heatsink mounting is a nightmare, which may explain the mess 😀
I have no complaints though. Many cheap motherboards lack any TIM at all on chipsets and mosfets.
Did countless repairs on burned down VRM's.

rasteri wrote on 2022-07-31, 08:44:

I quite like that it can be powered from a single 12V input, and that it has LVDS - some interesting embedded enclosure designs would be possible.
DOS iMac anyone? 😉

My thoughts exactly )

Well, what started as in impulse purchase now is beginning to shape into my personal dream-build of all times.

By using CPUSPD utility (KUDOS to kalohimal!) this motherboard becomes the most versatile DOS gaming machine.

1) 852gm gpu does have 3d support (idk how good though, did not test)
2) 852gm vbios can be customized and then added to BIOS to run different resolutions. I'm yet to try forcing 320x200 13h mode and feeding through a 1:5 scaler to a 1600x1200 monitor.
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)
5) ODCM CPU modulation 1 to 8
6) Chipset throttling 1 to 8
7) Cache on\off
'8)' DDR Frequencies 200\266\333

That alone gives me about 2048 possible speed combinations. And even more could be had by swapping CPU (about 256 combinations for each additional multiplier)

It's currently been able to run all speed-sensitive games I've thrown at it. And some play animations more fluently than on emulator or native hardware.
On the other side, all BUILD engine games, Nascar Racing and other late era stuff run as perfect.
The build is coming along nicely, I'm in the process of designing a soundcard and choosing a compact 12v psu.

But, alas, love is blind after all. The quality of the motherboards is not so good. (It is to be expected, as some of the chips are refurbished ones)
I'm already having some real problems with one of them.
Either RAM IC or Northbridge component went dead after a couple of power ups. I'll swap the RAM chips and see how it goes.

Below is a graph to show benchmark score of 256 speed combos (out of 2048) and the lowest score possible.

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

2) 852gm vbios can be customized and then added to BIOS to run different resolutions. I'm yet to try forcing 320x200 13h mode and feeding through a 1:5 scaler to a 1600x1200 monitor.

Success!
By modding vbios timings, I've been able to run natively 1600x1200@60hz and 1920x1200@60hz resolutions in DOS, which both scale 320x200 perfectly (x5 and x6 respectively)
Both are selectable via BIOS setting. No more fuzzy scaling!
HP LP2065 and Dell 2007FP both tested fine at 1600x1200@60hz
Dell U2412M (16:10) tested fine at 1920x1200

Awesome! Might have to grab one myself...

In case someone would need these, I've attached my BIOS dumps and the modified version as well.
Those BIOSes differ in some way from one mobo to another (option roms, microcodes, etc).

Modified BIOS Changelog:
- Updated VBIOS ROM from build number 1235 to 1270
- Added VBIOS Panel Data for 1600x1200@60Hz and 1920x1200@60Hz
- Modified Panel menu to reflect changes
- "Useless" resolutions are now hidden from the list (It actually can hold 16 panel options, so I could make a complete list, but I don't see any reason to add any other than 4:3 or 5:4)
- Added LAN boot ROM for RTL810x
- Contains CPU microcodes from one of the BIOS dumps

Anyway, I'm extremely pleased with the results.
It's a shame though, that it does not have DVI output (which 852\855GM is capable of).

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

The build is coming along nicely, I'm in the process of designing a soundcard and choosing a compact 12v psu.
<snip>
Either RAM IC or Northbridge component went dead after a couple of power ups. I'll swap the RAM chips and see how it goes.

Hello, first time post here from me, hope I am not doing it wrong.

I am looking at this motherboard as my attempts to revive vintage hardware for a DOS game machine have all failed.

What 12v PSU did you end up getting? Have you had any other hardware failures and were they fixable? How much did shipping cost from China?

I am looking at a Cooler Master NR200 Mini-ITX case for one of these as it has three expansion slot openings that seem to align right and be the right height from my eyeballing, as I'll be adding an Orpheus II LT to it.

Hope I will have something to add to this thread later if I can get one of these.

Hey, snap! I ordered one of these from China in late November as a Christmas present to myself and it just arrived. Felt like a bit of a risk, but the company reps were helpful over chat, it turned up and powered up on a table fine. I haven't had much chance to play with it. Maybe we can compare notes.

Context: I want a relatively small dos/Windows 3.11/win98 box for nostalgia. It (obviously) doesn't have to be period perfect, just run the majority of the games I played as a kid with sound and give me a few things to tinker with. I have various parts I've kept from early 2000s, and I'll be recycling what I can - CDROM, old atx PSU (if the voltage looks ok), maybe a floppy, mixed in with newer (cheap) hardware (Eg sdcard or CF for storage). I've already blown my budget with the motherboard - I still need to find a case, PSU solution, and I've ordered one of the new-old rage xl PCI cards to see what effect it has on FPS in games like half life and quake. Those cards are supposed to work well in Windows 3.1 too.

The board is a mATX according to my ruler so it won't fit in any of the mini-itx cases I looked at, unless they're unusually wide. That, and the fact my ISA sound card is full height (ruling out slim mATX cases) means I'll probably end up with a mid-tower case with my full size cd-rom, maybe a compact flash slot, and floppy drive exposed on the front panel. This is larger than I envisioned, but if I have the drive bays I figured WTH - if I have the bays, I might as well have all the drives.

What 12v PSU did you end up getting? Have you had any other hardware failures and were they fixable? How much did shipping cost from China?

Right now, I have a modern ATX psu running through a https://amzn.eu/d/gYVR1p1 to turn the PSU on and off, which supplies the needed 12v. That's just what I had on my "bench". I'm just feeding the board using the 4-pin cpu 12v connector from the PSU.

I'm also using that board to power a raspberry pi pico-based usb to serial adapter to give me a serial mouse. So far, I have been unable to get a PS/2 mouse working with the motherboard, though I only have an untested ps/2 mouse available so there may be nothing wrong with the motherboard.

I'm not very familiar with motherboards, but I don't know what I'm going to do about power when I get a case as this one looks weird. The motherboard manual linked above isn't very clear, so I've yet to work out the significance of the PS_ON jumper - I will play. Usually, I think something would be fed from the motherboard to a PSU to tell it to turn on the 12v rail, and there would be connectors to the board for the momentary case switch, and the motherboard would be using the "always on" 5v rail for PSU control logic. With the usual 20/24 pin connector, the motherboard would be responsible for taking the momentary button press from a case button and latching the PSU on. Here, the motherboard requires 12v to do anything and creates all its own other voltages like the 5v, so it looks like some of the circuitry/connectors are deliberately "missing". That implies to me that I would probably need to create my own PSU latching circuit and leave the motherboard in "boot immediately" mode and starved of power (which I think is the purpose of the PS_ON jumper), or always have 12v fed to it and see how the other jumper position works (though I don't know how I would signal the board to "soft boot" right now as I couldn't see a connector for the case power switch).

Hope I will have something to add to this thread later if I can get one of these.

I'll try to add things as my build takes shape too!

BTW - if you're still undecided, I also looked at the Nixdorf Beetle/M POS computers selling for the same kind of price as this motherboard on eBay in the EU right now. They seem to have a similar P3/pentium M ISA bridge setup, but with a compact case and full height(?) card slots. I wouldn't have been able to have a physical CD-ROM drive in that case so it wasn't ideal for me. I can't speak for how well it would have worked as I went with the isa855 instead. The POS computer would less hassle and more compact, but part of the fun for me here is in the journey, not the destination, so having a few problems to "solve" is good.

Discoveries: searching for IA855 (the model stamped on the board) instead of ISA855 led me to the manual in Chinese (https://www.piesiatech.com/intel-855-mini-itx/ia855). Google translate does a better job of producing English than the English ISA855 version posted above. Things like:

ISA855 manual: "This product is special design, input power supply counter-motherboard can be automatically protected, but can not protect high voltage."
Vs Google translate
"This product is specially designed to automatically protect the motherboard when the input power supply is reversed, but it cannot protect against high voltage."

....but there's no new information I can see.

Aside: Probably not specific to this mobo, but the ATI rage xl card I ordered works better in dosbench than the built-in VGA. Plugged it in and it just took over primary display adapter duties, as expected. I have some numbers (approx. 150% faster generally), except for quake (only) at 640x480 where it was about 50% of builtin until I tried "fastvid". VESA compat seems better too. I don't imagine this is specific to this mobo.

Ignore my mention of floppy drive from my previous post. The motherboard doesn't have a floppy header, so if I want a floppy I'm going to need a floppy controller. It might be possible to squeeze a homebrew floppy controller in my one remaining ISA slot, but I think the pci closest to the I/o shield may be too close for mATX(?) so I may have used my two slots with ISA sound and PCI graphics. Mechanically, having both PCI and ISA populated in the shared slot may be possible if one doesn't have a bracket, but tight! I don't really need a floppy, so that would purely be a "for soldering practice" project. It might be a fun way into understanding how additional ROMs work if the main bios doesn't support floppy. I've never seen a pci-based floppy controller, I wonder if such a thing is possible. If that other PCI slot can't have a bracket it will be going spare.

I installed intel chipset drivers from philscomputerlab for win 98. I've had a few bluescreen failures to write to my c drive (actually an ide-to-sdcard adapter) while playing, so that's not great. No obvious pattern. I'm going to try a compact flash card instead soon, maybe a different IDE cable. I will try older drivers if that doesn't help. It wasn't running for long enough without chipset drivers to know if it's likely to be hardware or drivers, but I haven't seen this problem with the sdcard adapter on other boards (only pentium 233 and similar).

On the power front, the PS_ON jumper appears to be "treat power switch as momentary" (closed), "treat power switch as toggle" (open). That makes sense from what I remember about AT Vs ATX power buttons. The FP1 (front panel) connections for reset switch and power work as normal ATX with PS_ON closed, and a windows 98 shutdown leaves the motherboard in a soft power-off state. Green LED1 on the board (not marked in the manual) appears to indicate 12v is coming to the board, while LED2 next to it indicates the "soft" power state. I notice there's an option in the bios that suggests other things besides front panel (like keyboard) could be used to signal the board to "soft power on".

On the power front the final wrinkle for me will be avoiding having 12v supplied to the board the whole time. On my bench ATX PSU means the fan would be running constantly. My bench PSU has an on/off toggle switch (and my final PSU probably doesn't) though I don't really want to use that, or the (UK) wall switch, as part of sitting down to use it. I could run a toggle switch to the front panel and use it to ground pin 14 (turning on the 12v), just ignore the power button built into the case. Perhaps if it's a DPST I can put the board into AT mode and have the other pair go to the front panel power connectors on the mobo too. Shame to not use the case switch, though.

I may dig more into the BIOS next as I think most of the electrical curiosities are complete. I've kept a lot of the built in peripherals (USB controller, sound, modem) turned off in bios so far, but I suppose now I've got win98 running I should try them out to see what they're like - my ISA soundcard is a cheap sbpro compatible, so the built-in sound may be better for win98 directx gaming. I should probably get to the bottom of the ps/2 mouse issue too. I also notice my win98 install seems to think there's a second generic graphics adapter sitting on irq10 even though I've turned off the on-board graphics in bios. It may be residual mess in the install from me playing around, but it comes back if I remove it suggesting there's something there to be found. I may try the on-board graphics with its driver under win98 to see what it's like for playing something like half life or c&c.

More info for future travellers...

I tested the built-in audio under Win98 SE. The AC97 codec on my mobo is a realtek chip (ALC655). I got it to work with a realtek driver bundle for Win98.

Having done more research on the mATX standard, the board's 3 bracket positions (1 PCI, one shared PCI/ISA, one ISA) are arranged according to normal mATX dimensions. It came with an mATX I/O shield and a couple of other cables for SATA data / power. I haven't tried the SATA connector yet.

This may not be specific to this motherboard, but a modern 8GB 133 Transcend CF card I bought did not work with a cheap IDE-to-CF adapter I bought. The only other CF card I currently have is a very old 16MB (yes, MB) card, and that works. The 8GB card did work in the CF slot directly on the motherboard. I have another startech 3.5" slot CF adapter ordered and will try it, but I expect it not working is due to an IDE BIOS limitation that the mobo's own CF slot isn't subject to.

I could not get a Soundblaster Live! card I had lying around to work in the motherboard with Win 98 SE, but it sounds like driver compat is a fairly common problem with this card and I'm going to stick with the ISA sound card anyway.

RetroFlump wrote on 2023-12-20, 22:52:

The 8GB card did work in the CF slot directly on the motherboard. I have another startech 3.5" slot CF adapter ordered and will try it, but I expect it not working is due to an IDE BIOS limitation that the mobo's own CF slot isn't subject to.

I could not get a Soundblaster Live! card I had lying around to work in the motherboard with Win 98 SE, but it sounds like driver compat is a fairly common problem with this card and I'm going to stick with the ISA sound card anyway.

I just got mine!

I am using a no-name 8GB CF card in the built-in slot. The ONLY way I could get anything to boot on this was by sticking the card in a USB reader and directly mounting it in QEMU in another machine and installing FreeDOS on the card and sticking it in the slot. I tried attaching a USB CD-ROM and booting FreeDOS liveCD and a few other things and it recognized the drive but nothing would boot. ISO on USB did not work (BIOS says 2003 I guess that is why.) I have no IDE drives to test, haven't tried SATA.

For sound I have a newly-acquired Orpheus II LT, the reason I got this mobo is it's new (manufactured in 2023 according to sticker) with an ISA slot, for this card. Long story short, it's been trouble and I still don't have it fully working after a day. Some games don't have sound effects but music works. DOSMID can do wavetable. Adlib Tracker 2 (again the reason I built this thing) plays gibberish. I've tried turning PnP on and off for the designated IRQ and DMA and tried changing the IRQ and DMA around multiple times no dice so I wonder if it just doesn't like some cards. Disappointing. Gonna talk in the orpheus II thread to try to troubleshoot it in case it's me not the board.

adlib tracker 2 didn't work right at its native resolution, the video was present but heavily distorted. I forced it to 1024x768 and it worked fine though.

Other info for people looking to get one of these:

I got this power supply: https://www.amazon.com/dp/B07MXXXBV8
and this barrel adapter to molex: https://www.amazon.com/dp/B0BRHHJ32Z

no 5v but seems to work fine maybe that is why the sound might not work right? I don't know how this works I am a simple man.

Really hoping I can get the sound problems worked out because this is meant for playing with OPL3 sound production.

moon wrote on 2024-01-03, 09:29:

For sound I have a newly-acquired Orpheus II LT, the reason I got this mobo is it's new (manufactured in 2023 according to sticker) with an ISA slot, for this card. Long story short, it's been trouble and I still don't have it fully working after a day. Some games don't have sound effects but music works. DOSMID can do wavetable. Adlib Tracker 2 (again the reason I built this thing) plays gibberish. I've tried turning PnP on and off for the designated IRQ and DMA and tried changing the IRQ and DMA around multiple times no dice so I wonder if it just doesn't like some cards. Disappointing. Gonna talk in the orpheus II thread to try to troubleshoot it in case it's me not the board.

Are you running the cpu at full speed? Maybe the cpu is too fast for the sound to work properly.

janih wrote on 2024-01-03, 11:19:

Are you running the cpu at full speed? Maybe the cpu is too fast for the sound to work properly.

Using a tool called Throttle and throttling 75% did in fact fix sound effects in DOOM! (But not in adlib tracker 2.) Thank you.

Adlib Tracker 2 has a delay/wait-state option that you can set, not sure specifically where/how. Has been a while. I had to do it on my 5x86 system w/CT2230 SB16, so it doesn't surprise me a Pentium 4 type CPU would have issues.

moon wrote on 2024-01-03, 12:01:

janih wrote on 2024-01-03, 11:19:

Are you running the cpu at full speed? Maybe the cpu is too fast for the sound to work properly.

Using a tool called Throttle and throttling 75% did in fact fix sound effects in DOOM! (But not in adlib tracker 2.) Thank you.

Beside CPU speed, other common issues preventing ISA sound working correctly involve USB\COM\LPT\AC97
USB can conflnct with upper memory DOS region. It does not have good support under DOS either. De-clocking CPU also makes USB inoperable, just stick to PS/2
COM\LPT use IRQ, which can lead to conflicts. Try disabling or changing their default IRQ's.

I'm not familiar with Adlib Tracker, but I'll try to give it a go and see how it works on my build

Paul_V wrote on 2024-01-03, 13:39:

I'm not familiar with Adlib Tracker, but I'll try to give it a go and see how it works on my build

Thank you! However, changing a setting in the at2 settings did fix it, so it is not necessary!

The board now is my dream DOS computer.

moon wrote on 2024-01-03, 09:29:

Other info for people looking to get one of these: […]
Show full quote

Other info for people looking to get one of these:

I got this power supply: https://www.amazon.com/dp/B07MXXXBV8
and this barrel adapter to molex: https://www.amazon.com/dp/B0BRHHJ32Z

no 5v but seems to work fine maybe that is why the sound might not work right? I don't know how this works I am a simple man.

I'd be careful with these. That MOLEX connector at the bottom of the motherboard is power output for HDD, not input.
Applying 12V *should* work, as it's probably a straight connection from main 12V rail.
But 5V definitely comes from regulator within the motherboard, applying that voltage to molex connector may damage the MoBo.

Main power connectors are at the top - 4-pin ATX molex and 2-pin 3.96mm Pitch JST