maxtherabbit wrote on 2025-12-10, 00:14:

all 30-pin modules are pretty much guaranteed* to NOT be EDO however... the 3-chip layout has different memory refresh requireme […]
Show full quote

all 30-pin modules are pretty much guaranteed* to NOT be EDO however...
the 3-chip layout has different memory refresh requirements and will simply not work in some older boards

I suspect this board just will not work with 3-chips and requires 9-chips. FYI the 3rd chip which is different is indeed the parity chip

*new production stuff notwithstanding, some ebay sellers actually do make them with EDO

In my searches for parity modules on amazon, I did indeed find edo 30pin.

https://www.amazon.com/Keystron-30pin-Memory- … cs%2C212&sr=1-5

Almost certainly new product, but the caveat emptor exists.

tony359 wrote on 2025-12-09, 21:26:

weedeewee wrote:

Hey Tony359,

Is there any reason you haven't posted photos of the modules that work and the modules that do not work ?

Senility? 🙂

I just forgot. I’ve just noticed one chip is different from the others

ahum...
are those the ones that are working, or are those the ones that aren't working?

the ones which are not working - I clearly didn't fully read your message, apologies! 🙂

Mind posting a photo of the ones which are working ? 😀

I’m slow, right? 😂

These both work

I'll have a look in my collection when I take the time to see if I have some 30 pin sim modules that have a similar "AM MI514100J-70" chip on them.

I've managed to disable parity error check in the BIOS with good RAM and now the RAM in question works fine with parity disabled. Thank you all!

tony359 wrote on 2025-12-12, 18:12:

I've managed to disable parity error check in the BIOS with good RAM and now the RAM in question works fine with parity disabled. Thank you all!

it would seem that the RAM in question has a bad parity chip on one of the modules and the other system in which it was working just had parity checking similarly disabled

But I tried each one of those modules with three other good modules and I keep getting the same error message.

Have you considered that those modules that give a parity error when parity is set to enabled have fake/bad parity chips ?

I would've suggested to exchange the parity chip of one of the non working ones with one of the working ones,
but since I can't find a datasheet on the non working ones, even though i do think they'll have the same pinout,
I'm not willing to recommend it.
But if you're up for a , probably rare possibility, of , worst case, killing a working ram module then do go ahead and swap the parity chip and then test it.

weedeewee wrote on 2025-12-12, 19:01:

Have you considered that those modules that give a parity error when parity is set to enabled have fake/bad parity chips ?

Interesting. I don't think they are bad as as I said, I tested each one of them with three from a working batch and they did not work.

Fake is a possibility. As you say, since I can make them work by just disabling the parity, I'm good with that 🙂

I test the RAM at some point in this video, this thread linked in the description - and Vogons mentioned! Thanks a lot as usual!

https://www.youtube.com/watch?v=mQQwNxSiEEU

tony359 wrote on 2025-12-12, 19:37:

weedeewee wrote on 2025-12-12, 19:01:

Have you considered that those modules that give a parity error when parity is set to enabled have fake/bad parity chips ?

Interesting. I don't think they are bad as as I said, I tested each one of them with three from a working batch and they did not work.

Fake is a possibility. As you say, since I can make them work by just disabling the parity, I'm good with that 🙂

What if they just all 4 have bad parity chips?

I mean parity is kind of a meme anyway so I don't blame you for disabling it and just carrying on but I'm still curious what's going on here. What if they came out of a system that experienced some kind of electrical damage on the parity line of the memory bus and it cooked all 4 of them?

maxtherabbit wrote on 2025-12-13, 23:06:

What if they just all 4 have bad parity chips?

I'd say unlikely but possible.

I should test them on some other boards for sure.