jheronimus wrote on 2021-09-09, 16:03:
Thank you so much for the manual — this is simply an insane find! At a quick glance it doesn't offer much insight into those jumpers (I was hoping there's a VLB speed divider somewhere), but I'm sure it will give some useful info.
My pleasure! I'm glad to share it! I have been meaning to make a copy of it, and when you asked, it reminded me that that was on my to-do list. It really does not offer much to tell us what those myriad of "factory default" jumpers do, but perhaps there's someone out there who's experimented? I haven't found much. It seems that these boards were so unpopular and uncommon that perhaps we're some of the first to really tinker with them and explore.
I believe both boards are very picky about the RAM you use. I ran memtest on my Biostar with a set of FPM sticks that I used on a lot of my 486 boards with no issues and it simply gave me a ton of errors. So maybe I should run the same test on Supermicro and I could use tighter timings with a different set of RAM.
Funnily enough, I found my boards to be less picky than I expected. I used standard FPM SIMMs, although they might be more compatible by virtue of being HP-branded NEC SIMMs. I have a bunch in my Vectra 486/33n, and liked them enough that I figured I'd give them a go here. I actually haven't tried memtest though; that's an interesting call--I might check and report back on that. I wonder how the Northgate does with a WinChip2 in something more diagnostic and strenuous like memtest. I should see and report back.
I can't remember the specifics of using alternate BIOSes, but I remember that in general they were slower than the original Supermicro and somewhat less stable. I was having high hopes for the Biostar boards, because I've thought that Award boards didn't block the non-Pentiums, but it's not the case with Biostar, unfortunately.
Dang, this is not what I wanted to hear. I figured they'd be less stable, but slower too? That's not great. I guess I can live with the tricky SuperMicro BIOS and see how things go. The Biostar board might be a better option, just as my Northgate might similarly be more of a compelling pick, in such an instance. I guess I can really test and see once I replace the CMOS battery. I have one sitting on my desk, but haven't had time to solder it on, as I just started classes. Hopefully, this weekend or perhaps next week will provide more time haha.
Huh, guess I might have a dead WinChip after all, I should test it on a more common board.
I sure hope not! Please keep me posted! I know that, for some reason, the Northgate is weird when I configure it in specific ways. For example, it likes certain VLB cards, like my Trio32, and then sometimes it won't play nice, and I have to pop-in a Vision864, which it seems to work just fine with always. It must be something with that Phoenix BIOS. I'm not the biggest fan, as you can probably guess.
It even says the same on their website.
As to whether I have a later, "fixed" revision of the board, or if perhaps the 546 and 596 are interchangeable, I am not certain, but the fact remains that there is reason to suppose both could be true.
Interestingly both our boards are rev.3, but yours has these red elements (I don't know what they're called) while mine doesn't. Don't see any other difference in layout.
This is something I'm quite interested in. I did also notice that my SuperMicro board only has the OPTi Premium branding on the 597, but not on the 546. What a weird thing. Heck, even the board on Ultimate Hardware 2019 doesn't have the chipset configuration that mine does...
I wonder if the difference is more-or-less superficial, like the PCB revision differences on the Alaris SLC2/BL3 boards. I, for example, have an RYC/Alaris 486SLC2 that has a slightly different layout and slightly different colored components than some other forum members here do. I believe mine is slightly different from Anonymous Coward's, for example. But, performance is the same, and I figure that the same is probably true here. Although, that 546 might play a bigger role in that; or it might not, and I'm pontificating aimlessly haha
If I am not mistaken, few, if any of these boards were sold in retail, most of them were only available via small system builders. Again, according to Usenet, Supermicro didn't really provide user support — it's a miracle they even released a BIOS update or even acknowledged the board on their website. Then again, it seems to be one of their first products ever (the company started in 1993, a year before this board's time).
Makes sense. BitWrangler brings up a good point there too. These boards were not top-of-the-line, but more end-of-the-line. It's a shame, too. I happen to own a revision 1 of Anonymous Coward's NICE VL/EISA board (it's the same, but with a LIF socket), and it's like a distant cousin of this board, but, unlike the P54VL-PCI, it was just truly the highest end at the time. VLB and Pentium is a match made in hell, but it isn't completely awful if implemented well. I'd imagine that the Python/Cobra can perform at least in the vicinity of a 430LX/NX if configured properly. That said, the 430LX/NX are certainly going to have higher ceilings, even if their floor is approximate to the OPTi's maximum performance.
It's weird that you can't use PCI video (I didn't have that issue on either board). I think WaybackTech had the same exact problem with his TMC Socket 5 board, but he mentions he used a non-original BIOS. His board used a 571/572 chipset and acted very strangely in many regards and I think he had memory bandwidth that was even below 486 levels. So yes, it could be related to BIOS.
I gave this video a watch and found it interesting. He definitely has more issues with the BIOS than I do, but the Phoenix BIOS on that board just does not do it wonders. I'd be interested to try another, but my concern is about the integrated I/O being non-functional. Hilariously, that I/O is VLB-based, although I suppose that makes sense, since the PCI on these boards is bridged to the VLB anyway. Perhaps the direct VLB I/O is marginally faster than a bridged PCI->VLB I/O setup? Either way, I digress.
I don't think any regular MMX chip is rated for 3.3V. I haven't tried Win95 on Supermicro at all — only on Biostar, so can't comment there. But generally compared to DOS/Win3.11, Win9x is a lot more sensitive once you start picking tighter timings.
Out of curiosity, was the Win9x experience decent on the Biostar? I used to run Windows 98SE on a P166 and an AOPEN AP5C/P 430FX board, and it was more than usable. That was a main machine of mine for a while, and a family friend's before that.
That would be really cool. I've been looking for an image for a very long time in many places 😀
Hopefully we can find it sometime! It'd be a shame to be lost to history. I have been searching (and I believe Anonymous Coward has as well) for the MR-BIOS for the OPTi 295 chipset too. It would be great fortune if they happened to be on the same disc, and someone found that disc.
Off-topic here, but on the topic of nonexistent drivers and whatnot, I recently worked on a Paradise Accelerator Pro (IIT AGX-014 card), and getting that thing running was a nightmare. I had to use a VESA TSR for the Orchid Celsius in DOS, and Windows 95, as that had built-in drivers. Side note: These AGX cards are really weird. I would not recommend one for Windows acceleration either. Perhaps they were nice in Win3.1 with drivers...
Hopefully, our experience here fares differently and we can find these lost MR-BIOSes.
cyclone3d, I think you're right about that. Unfortunately, 66x1.5 is going to be the hard limit here, unless I were to bridge the BF0/BF1 pins and hard-mod the board or CPU for such an application. There's also the WinChip option, which reinterprets 1.5X as 4X.
As for the interposers, I saw a few on eBay for 486s, and grabbed one a while ago. There's an overpriced Socket 5/7 one out there that the seller wants an exorbitant amount for, so I'm learning towards finding an MMX OverDrive for this purpose. That, or the WinChip2 at 50x4.
Speaking of, anyone know how a 200MHz WinChip2 would compare against a Pentium MMX 166? I'd imagine they'd be close, no? The MMX 180 is probably the more intriguing OverDrive chip, in such a case.
Anonymous Coward wrote on 2021-09-09, 17:11:
The reason so many POD83s survived is because they were expensive and highly incompatible upgrades, and very few people actually bought them at the time of release. They sat around in warehouses in their retail packaging until they finally got listed on eBay at discount prices in the mid 2000s and snapped up by enthusiasts. Most other types of overdrives were unboxed and used, so were more likely to go to the scrappers.
Makes sense to me. I bought mine about 15 years ago on Amazon, and it was NIB. I've since used it a bunch of times, and it's been great. It was originally intended for my aforementioned Vectra 486/33n, which is supposed to be compatible. Well, it wasn't--until I found the updated BIOS sometime a few years back. It works fine now, but for years it was a nice testing chip and that's about it.
I haven't seen the OPTi EISA Pentium chipset used on other boards either. I've seen the original sales brochure, and I don't think it was designed for backplanes. I think it was just way too expensive to implement, so rarely used.
Huh, go figure. I haven't seen too many EISA Pentium boards anyway. It seems like there's more 486 ones out there, and the SiS chipset on the NICE Super VL/EISA is more than fast enough for some fun EISA action. I did see a dual Socket 5 EISA board a while back on eBay, but the price hurt to look at, and EISA on a Pentium isn't as compelling for some reason, at least not to myself.