Cga.8086 wrote:

i have this question for ages back in the day there was no good ram information on the stick hell in some you dont even know how […]
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i have this question for ages
back in the day there was no good ram information on the stick
hell in some you dont even know how much megs does the ram stick have.

in some you see an edo sticker. but thats not found in other edo sticks.

so lets suppose you see a ram stick online. how do you know of it is edo or fpm? if someone removed the edo sticker

asking this because there is a ton of 486 mobos that only work with fpm

if googleing the part number yeilds no results or mixed results

then you simply have to take a KNOWN fpm motherboard and a known edo motherboard , and try the stick to see if they work and what size they are.

I just recently tried to add some ram to a 386n which uses fpm ram , only to find out that out of the dozens of stick I have ALL of them were edo and none where fpm except the one original stick in the machine.

I've got a P100 that tells you in the BIOS which mode the RAM is operating in so maybe that's an option if you have a board that can support both. Only drawback is being a Pentium it needs two matching RAM sticks, so if you only have one stick you want to check...

Probably looking up part numbers on the chips is the most reliable. That will tell you the capacity, speed and operating mode.

A lot of Socket 5/7 boards will report the memory type in each row.

It was clarified some time ago: Re: Q: EDO vs. FPM - how to tell which is which

lazibayer wrote:

A lot of Socket 5/7 boards will report the memory type in each row.

This is my method too.
The part number way looked promising but then I took my FPM and EDO boxes out of the cupboard and I saw that either it doesn't work or I made a lot of mistakes when I sorted my SIMM sticks 😵

lazibayer wrote:

A lot of Socket 5/7 boards will report the memory type in each row.

And the FIC PA-2002 and PA-2005 should be able to run single SIMMs, making it easier and perhaps more convenient when testing lots of unknown SIMMs without having to use several different boards due to compatibility problems.

You may still be able to order the older memory testers at http://www.memorytesters.com/products.htm
Not sure if the 72-pin SIMM modules (no shown on the site anymore) are able to discriminate between FPM and EDO, or if they just count the RAM quantity and test the response time. Last I checked with them, which was about 2 years ago, they still had some older units for sale.

TC7400AJ6 = FPM ("00" after "TC74") :

Trick works 😀

agent_x007 wrote:

TC7400AJ6 = FPM ("00" after "TC74") :

FPM.jpg

Trick works 😀

ther must be a like 50 different makers
that code only works for that maker

Cga.8086 wrote:

ther must be a like 50 different makers
that code only works for that maker

I assume you didn't read the thread BastlerMike linked? Apparently it works for many manufacturers.

i
just
found
soooooooooomething...... really nice when you look at the chips

http://fthain.github.io/dram/

The "number trick", posted by BastlerMike, worked for all sticks that I have.

Cga.8086 wrote:

i
http://fthain.github.io/dram/

Wow, thanks, it helped with some of the more cryptic pieces. Now I've narrowed down the uncertain set to one pair that was probably in the wrong box. This pair goes to the TX board, let's see what it says.

The quick method I use when sorting out PS/2 memory sticks is:
- first, throw away everything that doesn't have "6 pins in a group". The chips on the picture above have 24 pins which means this is either 16MB (single side) or 32MB (double side) SIMM. I don't care about anything with 20 pins only
- then test them with MEMTEST in one of my systems

I don't care much if they're EDO or FPM. So far, most systems are happy with EDO (including old Macs or Atari ST). However, a quick method is to check the last two digits of the chip type. FPM typically have 00 here, while EDO is 04. Sometimes, this specifies refresh type, and if you see other numbers than 00 and 04, you'd better check the chip's spec.

Kubik wrote:

The quick method I use when sorting out PS/2 memory sticks is: - first, throw away everything that doesn't have "6 pins in a gr […]
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The quick method I use when sorting out PS/2 memory sticks is:
- first, throw away everything that doesn't have "6 pins in a group". The chips on the picture above have 24 pins which means this is either 16MB (single side) or 32MB (double side) SIMM. I don't care about anything with 20 pins only
- then test them with MEMTEST in one of my systems

I don't care much if they're EDO or FPM. So far, most systems are happy with EDO (including old Macs or Atari ST). However, a quick method is to check the last two digits of the chip type. FPM typically have 00 here, while EDO is 04. Sometimes, this specifies refresh type, and if you see other numbers than 00 and 04, you'd better check the chip's spec.

w00t big thanks 😎

Problem is that that sort of rule-of-thumb is vendor-specific. It's better to look up the nomenclature of the chip vendor involved:

Here's a good place to start
http://idhw.com/textual/guide/noin_ram_chip.html

Frequently a 0 somewhere indicates FP and a 3,4, 5, 6 or even 9 indicates EDO, but the exact place can differ and sometimes higher numbers can be used for FP too (particularly the 3 is troublesome), so if the SIMM isn't in the list already posted above (http://fthain.github.io/dram/), go to idhw and look up which position and which numbers to look for.