You might get lucky looking up the part number, though sometimes one does not.
I guess this page is a good starting point http://martenelectric.cz/simm-sipp-ram-chip-database.html

weedeewee wrote on 2022-02-18, 21:47:

You might get lucky looking up the part number, though sometimes one does not.
I guess this page is a good starting point http://martenelectric.cz/simm-sipp-ram-chip-database.html

Thank you for the tip, looking for part number was something I wa trying to avoid there are so many models and not always the pdf with details is available.

But I got a solution, I updated the bios and now during the post it shows normal for fpm memory and EDO for edo...

Part number of the chips (not SIMMs) is usually pretty clear. If searching for datasheet lists "EDO", then it's EDO. If not FP/

dionb wrote on 2022-02-18, 22:30:

Part number of the chips (not SIMMs) is usually pretty clear. If searching for datasheet lists "EDO", then it's EDO. If not FP/

Well not always unlucky I wasn't able to find some datasheet and sometimes I labelled wrong the size, like: OKI M5117400a-60sj
I thought they were 16mb sticks, instead they are 32 mb FPM 😁

By numbers on chips. Zeroes on the end - FPM (example above: OKI M5117400a-60); 2, 4, 8, etc - EDO.

Nemo1985 wrote on 2022-02-18, 22:02:

But I got a solution, I updated the bios and now during the post it shows normal for fpm memory and EDO for edo...

Cool! There's a similar feature in Intel motherboards with earlier AMI-based BIOS

jheronimus wrote on 2022-02-18, 22:54:

Nemo1985 wrote on 2022-02-18, 22:02:

But I got a solution, I updated the bios and now during the post it shows normal for fpm memory and EDO for edo...

Cool! There's a similar feature in Intel motherboards with earlier AMI-based BIOS

Good to know, unlucky the socket 7 intel chipsets require 2 sticks of the same simm.

Nemo1985 wrote on 2022-02-18, 22:47:

dionb wrote on 2022-02-18, 22:30:

Part number of the chips (not SIMMs) is usually pretty clear. If searching for datasheet lists "EDO", then it's EDO. If not FP/

Well not always unlucky I wasn't able to find some datasheet and sometimes I labelled wrong the size, like: OKI M5117400a-60sj
I thought they were 16mb sticks, instead they are 32 mb FPM 😁

OKI M5117400a-60sj

4-Word x 4-Bit DYNAMIC RAM : FAST PAGE MODE TYPE

That's pretty clear: FPM

But the distinction between 16MB and 32MB is more interesting. These are 4Mx4 16Mb chips (pretty standard for later 72p SIMMs). 8 give 16MB total, 16 (8 on both sides) give 32MB total. If you expected 16MB, that implies that there only were 8 of them on one side of the SIMM (or 9 with parity). 32MB implies 16/18 of them, 8/9 in each side. If you were expecting 16MB and getting 32MB, something strange is going on...

Well... there are 16 chips, 8 for each side. I were expecting 16mb because according to what I was able to find I did the wrong deduction.

Anyway I took the chance to do some testing:
OKI M5117400a-60sj 32mb FPM x2:
Quake: 35,7 fps
Main memory speed: 78,6 MB\s 13,3 ns\byte 6.8 clk

IBM 11D8325BD-60J 32mb EDO x2:
Quake: 36,7 fps
Main memory speed: 92,2 MB\s 11,4 ns\byte 5.8 clk

Both with turbo settings.

So I haven't experimented a lot with 72p SIMMs, but I did see that a rule of thumb is that if the individual memory chips have 4 sets of 6 legs, each chip will have 2 megabytes (so 8 or 9 of these chips make 16MB and 16 or 18 (usually half on each side) would mean a 32MB SIMM).
If the individual chips have 4 sets of 5 legs each, then the memory size is 4 times less (so half a megabyte for each chip).

There's usually 3 different sizes of chips used on 72p SIMMs (excluding the more older and obscure ones) which are most commonly used for pentium class motherboards. The ones with 4x6 legs on each chip, the ones with 4x5 legs on each chip, and the very long chips with one very long row of legs on ech side of the chips.
These chips are also 2MB each and are usually found with 2 of the very large memory chips on each side. 2 of these chips on a side with both sides filled up will give 8MB total for the whole SIMM. I've seen some which have 4 of the very large chips on each side (the SIMM will be a bit taller to make room for a second row of 2 chips on the PCB) and these SIMMs will be 16MB.

I have a very few 72p SIMMs which have very flat and more square-ish looking chips which look more similar to what one could find on the first gen SDRAMs (the 16MB or 32MB PC-66 ones used for 430VX machines for instance) and these can be much higher capacity.

I didn't include everything of relevance and see this as a rule of thumb only and not a golden standard. This however made it easy for me to sort large amounts of modules quickly and recognizing modules quickly if I just wanted a set of SIMMs for a quick test in a hurry.