That ebay listing looks ok to me, assuming it works. I think it's slightly older than the AOpen board you have, but it has 512kB of cache and the clock chip and regulator may allow some nice upgrades. You might be able to find documentation for it on the retro web as a PC Chips board to see if it has all the features you want. The newer super socket 7 boards will usually be faster, but also more $$.

I have an older PC Chips M530 (ca 1996) that is now maxxed out with a K6-3+ CPU and working great with some help from people here. Good luck!

Replacing a very good AOpen board with i430HX chipset with Elpina (=PC Chips) board with Via VPX chipset? Doesn't sound like a great option...

dionb wrote on 2025-07-30, 21:27:

Replacing a very good AOpen board with i430HX chipset with Elpina (=PC Chips) board with Via VPX chipset? Doesn't sound like a great option...

Yeah, that's the AP53 rev 3, which has the dual plane/MMX support. A very solid board.

It may be a good board, but the RTC chip is a menace. I am trying to salvage it, this thread is to discuss a backup plan -- hence the request for suggestions.

Now that I think I definitely destroyed the motherboard trying to fix that rtc chip, all suggestions for a board that would be as good as the original will be appreciated. There's nostalgic value to this particular computer (it even has a name), it would be really nice to bring it back to life -- even with a different mb.

multiplebaboons wrote on 2025-07-31, 08:02:

Now that I think I definitely destroyed the motherboard trying to fix that rtc chip, all suggestions for a board that would be as good as the original will be appreciated. There's nostalgic value to this particular computer (it even has a name), it would be really nice to bring it back to life -- even with a different mb.

Just run a search on Theretroweb for boards with i430HX chipset, then look at the pics for battery type.

The obvious alternative would be the Acer V35N, as AOpen was Acer's retail brand so it's literally the same manufacturer, but apparently their OEMs wanted CR2032, not Dallas RTCs (and rightly so...). This gives you two extra SIMM slots and PS/2 keyboard and mouse instead of DIN AT.

Other decent-looking options would be things like
Chaintech CT-5IFM0
EPoX EP-P55-TH
FIC PT-2200
QDI P5I430HX
Supermicro P5-XTRA
- but unless you're living in retro computing paradise and have any and all boards available, you'll probably need to compromise with what's available.

The problem is that 1996 / i430HX era was peak Dallas era, so it's pretty eccentric looking for a solution that only became common a year or so later.

Two alternative options:
1) stick with i430HX, but look for boards with socketed Dallas DS1287 chips. Then you can just pull the dead one, do whatever work you want to it without risking the rest of the board and if it fails, you can get plug-in alternatives (or even completely new DS12887s - but buy them through a reputable electronics supplier, not eBay as most sellers there relabel old dead ones).
2) stick with So7 and CR-2032 battery. but look for i430TX boards from 1997 instead. Much higher chance of the config you want. You also get SDRAM support and overall higher performance. Only drawback is that TX can do max 256MB RAM and can only cache 64MB of that, so if you want lots of RAM this is a bad idea.

Thanks a bunch! And compromises are certainly okay with me.

dionb wrote on 2025-07-31, 08:26:

The problem is that 1996 / i430HX era was peak Dallas era, so it's pretty eccentric looking for a solution that only became common a year or so later.

Naw, not that eccentric. I would be okay with any decent board with that will accept the CPU and RAM I've got -- and a 2032 battery. Ideally, it should also fit the back of that case, which definitely gives you a big glory hole for that keyboard DIN connector.

dionb wrote on 2025-07-31, 08:26:

1) stick with i430HX, but look for boards with socketed Dallas DS1287 chips.

That is most certainly acceptable, especially now that I think I probably fixed the DS1287A chip... while messing up the board.

multiplebaboons wrote on 2025-07-31, 08:33:

Thanks a bunch! And compromises are certainly okay with me.

dionb wrote on 2025-07-31, 08:26:

The problem is that 1996 / i430HX era was peak Dallas era, so it's pretty eccentric looking for a solution that only became common a year or so later.

Naw, not that eccentric.

For 1996 and so i430HX boards it is. The vast majority of boards then shipped with Dallas RTC (or clones such as Odin)

I would be okay with any decent board with that will accept the CPU and RAM I've got -- and a 2032 battery. Ideally, it should also fit the back of that case, which definitely gives you a big glory hole for that keyboard DIN connector.

How much RAM do you have? If <=64MB, that requirement basically means any BabyAT motherboard that takes EDO (unless you have FP, in which case that caveat disappears too) , which widens the options a lot.

If you have >64MB (I see four double-sided DIMMs on your pic, that could be 4x32MB = 128MB) things get more complicated, as only a few So7 chipsets can cache >64MB, and that becomes the main criterion. Still, there's nothing stopping you going for say a late MVP3 board with 1MB of cache that would fit that description, even if it's a bit overkill.

dionb wrote on 2025-07-31, 08:57:

If you have >64MB (I see four double-sided DIMMs on your pic, that could be 4x32MB = 128MB) things get more complicated, as only a few So7 chipsets can cache >64MB, and that becomes the main criterion. Still, there's nothing stopping you going for say a late MVP3 board with 1MB of cache that would fit that description, even if it's a bit overkill.

I just pulled out the ram and it is indeed 128MB. Originally it had 64 and I upgraded.

multiplebaboons wrote on 2025-07-31, 09:14:

dionb wrote on 2025-07-31, 08:57:

If you have >64MB (I see four double-sided DIMMs on your pic, that could be 4x32MB = 128MB) things get more complicated, as only a few So7 chipsets can cache >64MB, and that becomes the main criterion. Still, there's nothing stopping you going for say a late MVP3 board with 1MB of cache that would fit that description, even if it's a bit overkill.

I just pulled out the ram and it is indeed 128MB. Originally it had 64 and I upgraded.

That complicates matters.

Your options are then:
- i430HX chipset with second tag RAM (either onboard or on COAST module)
- SiS chipsets (551x, 557x, 558x, 559x) with at least 512kB of L2 cache and a second tag RAM chip
- SiS chipsets with at least 1MB of L2 cache without the second tag RAM chip
- Via chipsets (VPX, VP2, PV3, MVP3) with at least 512kB of L2 cache
- older ALi chipsets (Aladdin III, IV) with 11b tag RAM (or 2x 8b)
- ALi Aladdin V chipset (any revision can cache 128MB, although from rev G onwards it can cache more)

There are enough boards out there that fulfil at least one of these chipset options, but it can be a challenge to figure out if a specific board does.

Maybe a step back: what are you running that needs 128MB? For DOS it's complete nonsense, for Windows 95 it's useless too; Win98 itself doesn't need it but there's Win98 software out there that might - but I don't think that would run on your CPU. The only uses cases for 128MB on a system this old are Windows NT (or 2k if masochist) or Unix/Linux.

In addition, the impact of uncached RAM is much bigger in DOS and Win9x vs OSs with decent memory management like WinNT/2k or Unixen.

dionb wrote on 2025-07-31, 09:40:

Maybe a step back: what are you running that needs 128MB? For DOS it's complete nonsense, for Windows 95 it's useless too; Win98 itself doesn't need it but there's Win98 software out there that might - but I don't think that would run on your CPU. The only uses cases for 128MB on a system this old are Windows NT (or 2k if masochist) or Unix/Linux.

I used to be a huge fan of 2k, but I've never been much of a gamer. For my uses, it was the first Windows ever that did not suck at all.

That aside, I had this machine running freeBSD a while back. For now, I was thinking 98/98SE to fully experience the adorable silliness. Aside from a few games, there is a somewhat non-obvious and very fun (at least for some) retro computing activity: scientific computations, which I highly recommend. I have a CD with old Matlab (circa 1998-2000 i think) and that thing will easily eat up 128Mb and then some, if you feel sadistic enough. I'm one of those people routinely consuming a terabyte of RAM for a single physics simulation, so if you give me any amount of RAM, I will find a way to make every node on that cluster start swapping. 😉

multiplebaboons wrote on 2025-07-31, 11:08:

[...]

I used to be a huge fan of 2k, but I've never been much of a gamer. For my uses, it was the first Windows ever that did not suck at all.

That aside, I had this machine running freeBSD a while back. For now, I was thinking 98/98SE to fully experience the adorable silliness. Aside from a few games, there is a somewhat non-obvious and very fun (at least for some) retro computing activity: scientific computations, which I highly recommend. I have a CD with old Matlab (circa 1998-2000 i think) and that thing will easily eat up 128Mb and then some, if you feel sadistic enough. I'm one of those people routinely consuming a terabyte of RAM for a single physics simulation, so if you give me any amount of RAM, I will find a way to make every node on that cluster start swapping. 😉

OK, then you definitely have a use case for that RAM 😀

Cache is faster than RAM, but uncached RAM is always much, much faster than swapping. I would recommend installing WinNT or 2k in that case. NT would be period-correct and would make much better use of the extra memory.

Still worth keeping an eye open for a board that can cache all of it though - or one that can handle even more. One of those HX boards with 6 SIMM slots would be nice. Note that HX can also use 64Mb chips so you can also use 64MB or 128MB SIMMs if you can find them - although max is still 512MB.

This forum is mostly about dos, but I would definitely be interested in hearing more about the scientific computing you're doing.

The damaged motherboard might be an opportunity to upgrade to a super socket 7? These boards can usually take more RAM and many support the K6-2+ (or K6-3+) CPUs that have L2 cache built into the chip. These CPUs can overcome the problem of cacheable area limits to a large extent, even under dos.

I've been running T2 linux with only 128MB of RAM (the limit on 430VX), and one nice feature of this up-to-date version is that it supports zram. This is a type of swap that uses compressed RAM as an intermediate "swap" stage before disk. Most software is very bloated and inefficient with RAM, so the compression works well and can breathe new life into older machines. So my 128MB of real RAM can sometimes work like 512MB before it hits the disk.

So I'm curious what you could do, starting with 768MB on a super socket 7 board.

Thanks for all the info!

What one can do on an old machine with megabytes of RAM is a whole variety of things. What I meant by scientific computations specifically in my case would be old Matlab scripts doing a bunch of very narrow-scoped toy things like solving differential equations, or doing Langevin dynamics of interacting spheres, or 3D motion of particles interacting gravitationally. Those would be CPU-intensive. Under Linux, one can get more serious with particle-based simulations and run very old versions of LAMMPS or Gromacs (also CPU-intensive, but can take up RAM if the number of particles is large enough). It is quite involved and became somewhat user friendly only maybe 10-15 years ago, but certainly something that can be fun. What can (and will) make any machine swap any time of the day is quantum chemistry. For something like 512-768MB of RAM, I think all you'd need for things to get nasty is to do a Gaussian (gaussian.com) run of something like carbon dioxide (three atoms!).

Incidentally, the first computational task I ever had to perform, and that was at a university physics olympiad, was under DOS (around '95-96) -- which I failed, because I could not program in BASIC, or any other language, for that matter. Come to think of it, combined with the recent failure to socket that RTC chip, these are my two most spectacular screwups. 😀