All specs say it supports ECC, can't find anything actually clarifying it actually requires ECC to boot. Wouldn't be too unusual for an OEM system with its specs though. I'd suggest sourcing a cheap unbuffered ECC DIMM and seeing what it does. Worst case you have good test part for the next board if this one doesn't want to boot with the ECC DIMM either.

If you've got any actual PC66 try that, it might need to see PC66 in the SPD, because IBM does crap like that.

I thought there was usually a different code for memory parity failure than generic memory failure.

I tried 14 different RAM configurations and none of them worked. I don't have a single ECC module so I have to buy a few to see if it's indeed the problem.
The board looks decent otherwise and even works with a dual 233 configuration. Diagnostic code 8810: 64K base memory test. 1-3-1 beeps confirm memory problem.
Possible DMA controller failure?

According to the IBM 3500 Series users handbook: "Working with Memory Modules
The memory modules that your server uses are dual-inline memory modules (DIMMs). The DIMMs that come with your server are synchronous dynamic random-access memory (SDRAM) with error correcting code (ECC). These memory modules have a speed of 66MHz. You can add extra memory modules or replace existing memory modules"

And under features states ECC DIIMS...Sounds like it must require ECC DIMMS or else the manual would state non EEC or ECC, long ago had a Compaq server board that also required them.

Took me long enough but I finally got it to work:
IBM Netfinity 3500 mainboard with dual Pentium II 233 CPUs.
Special thanks to Ram-co in Germany for yet another fast & flawless service!

Servers require ecc ram. That's a fairly early one, even predates my Intel SCB2 board (dual P3). I bought the board on ebay, knowing all along that serverboards can be picky about ram (often you need to check a list of compatible products). I personally haven't had any problems to date, bought a 2 module 2gb kit designated for some Gateway thing. So far my board throws error about the ram, the 2nd CPU. I don't know what any of it means as of yet. But I did install W2K AS w/o issues. Didn't even have a scsi drive handy, it only supports (2) ide devices on what normally has a cd/dvd drive hanging off it.

If you had put bad ecc ram or non-ecc ram, I suppose it shouldn't make any difference as far as beep codes go. If it's "bad" it's just bad.

chris2021 wrote on 2021-07-31, 03:55:

If you had put bad ecc ram or non-ecc ram, I suppose it shouldn't make any difference as far as beep codes go. If it's "bad" it's just bad.

True, beep codes didn't change. The diagnostic card showed different error codes though:
8803: no RAM
8810: wrong RAM (133 Mhz are not supported in any size)
The ones I bought and working are Micron 32 MB - 66, Micron 64 MB - 66 and Micron 64 MB - 100.
I don't know about your board but mine didn't work when I tried different speed processors. Two different 233 Mhz models of the same stepping worked (SL2HD & SL2HF) but a 233 and a 266 Mhz CPU didn't. I guess that's normal.

It's normal. Server boards, the ones I've seen, need the exact type of cpu in each socket.

Serverboards are just high quality motherboards that are built to run continually, higher class components, and can recover from errors that would o/w cause the os to blue screen. Hence the ecc memory.

But like I said yours is pretty early. I suppose the principles applied even then. There were, iinm, dual 486 motherboards, but don't quote me. I've never heard of anything prior to that.

My board uses a ServerWorks chipset, which is Broadcom. I hope I'm able to work out the bugs, even with the errors a single cpu setup seems to work with the ram I bought. All so I could run Delphi/Kylix, only to recently find out Delphi 6/7 *seems* to run under Windows 10, despite Windows stating 7 isn't compatible.