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Identify this RAM

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First post, by naujoks

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Who can identify this RAM stick, please?
Is it EDO or FPM? What size is it?
On the top right corner, above the white writing (which does not come off with IPA), you can faintly see "EDO" printed on every chip.
It was sold to me as FPM, but my 486 board won't boot with it (I have two sticks).

Reply 1 of 21, by dominusprog

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16MiB 60ns FPM.

https://picclick.ca/16MB-FPM-RAM-72-pin-4Mx32 … 6652235721.html

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 2 of 21, by naujoks

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The top picture that comes up with this is actually from the seller I bought it from, so that doesn't mean anything.
I just put the RAM in a Socket 7 board and there it is working, showing as 16MB.
So is it really EDO and not FPM?

Reply 3 of 21, by dominusprog

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The modules are 60ns for sure. The best way to determine the type and size is to install it on a motherboard.

https://ram-co-shop.de/Chip-Hersteller-QC_1

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 4 of 21, by naujoks

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That link is the same seller as on eBay, it's just his own website!

I DID install it in two motherboards! A 486 and Pentium Socket 7.

Reply 5 of 21, by Deano

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Send us a picture showing one of the chips and we can tell you for sure.
Motherboards can be fussy but the chip id doesn't lie unless faked which would be rare for common dram chips at the moment.

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Reply 6 of 21, by naujoks

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The picture is right there! You can clearly see "EDO" on some of the chips in the middle.

Reply 7 of 21, by dominusprog

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EDO or FPM, it should work on a socket 7 board nonetheless. Check all the traces and the solder joints.

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 8 of 21, by naujoks

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Ahhh but it's supposed to be FPM, and I need it for my 486 board!

Reply 9 of 21, by dominusprog

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Before buying any modules, search for the part number online first. And buy from a well known manufacturer like LG or Panasonic.

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 10 of 21, by naujoks

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Which part number?? RAM sticks don't have part numbers!
It seems I didn't make myself clear. Let me summarise:
I bought to FPM RAM sticks, they didn't work in my 486 board, they work in my Socket 7 board.
EDO is visible on the RAM ICs.
Was I sold EDO RAM instead of FPM?

Reply 11 of 21, by dominusprog

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naujoks wrote on 2024-09-25, 10:16:
Which part number?? RAM sticks don't have part numbers! It seems I didn't make myself clear. Let me summarise: I bought to FPM R […]
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Which part number?? RAM sticks don't have part numbers!
It seems I didn't make myself clear. Let me summarise:
I bought to FPM RAM sticks, they didn't work in my 486 board, they work in my Socket 7 board.
EDO is visible on the RAM ICs.
Was I sold EDO RAM instead of FPM?

44C400-60

Here's an example

GM71C4400BJ70

https://www.alldatasheet.com/view_datasheet.j … d=GM71C4400BJ70

Duke_2600.png
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!

Reply 12 of 21, by dionb

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naujoks wrote on 2024-09-25, 10:16:

Which part number?? RAM sticks don't have part numbers!

The chip part numbers, which are visible on your photograph.

It seems I didn't make myself clear. Let me summarise:
I bought to FPM RAM sticks, they didn't work in my 486 board,

You didn't mention this detail before. Clarifies situation a bit.

they work in my Socket 7 board.
EDO is visible on the RAM ICs.
Was I sold EDO RAM instead of FPM?

Sounds an awful lot like it. Your So7 board should tell you at POST what kind of RAM is in there, otherwise run a tool on that system that tells you.

There's something very shady about SIMMs with chips with two different and contradictory prints on them, from some obscure or non-existant vendor (a non-exhaustive list of genuin chip vendors can be found here, there is no "QC" on it). This reeks of relabeling, either recently or at manufacture.

If sold as FP, you should be able to return them. If you do so I'd recommend selecting new SIMMs with chips from a reputable manufacturer (see aforementioned list).

Reply 13 of 21, by MikeSG

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QC may have been bought by Samsung, and the part renamed from QC 44C400 (w/ EDO written on it) to HM44C4000C/HM44C4003C/HM44C4005C. The last "5" version is EDO.

https://www.alldatasheet.com/html-pdf/37285/S … KM44C4005C.html

If not Samsung, another large company may own it and have their own new part number...

Maybe every 1 out of 10 RAM sticks I look at is labelled wrong...

Reply 14 of 21, by weedeewee

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naujoks wrote on 2024-09-25, 10:16:

Was I sold EDO RAM instead of FPM?

I'm going to say, YES, to that question.
Also, What relabeled kind of chips are those, seriously WTF.

did those come from ram-co ? better let'm know & organize a return/refund, maybe an option for a correct one. if another seller, same.

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Reply 15 of 21, by naujoks

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They are from Ram-co, yes. Bought through eBay.
He's sending me two replacement sticks. He says he tested those sticks with RAMCHECK and also SIMCHECK II, and they're being reported as FPM. Previously sold sticks had no complaints. The replacements will be Motorola chips.

Reply 16 of 21, by douglar

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Holy Relabeled Ram Chips, Batman!

That's just egregious.

The attachment Untitled.png is no longer available

Reply 17 of 21, by mkarcher

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Wow! If they are going the effort to re-label the chip, why don't they put any name brand on it? QC is also known for the most likely part-defective chips used on ultra-cheap UMC SVGA cards like this one: http://www.vgamuseum.info/index.php/component … -umc-um85c405af . Their A413256 chips are 256K x 4 chips with one bad field (3 remaining), and A41256 chips have 2 bad fields.

Reply 18 of 21, by Many Bothans

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douglar wrote on 2024-09-25, 18:02:

Holy Relabeled Ram Chips, Batman!

That's just egregious.

This is as sketchy as 486-era SRAM with bright bold "WRITE BACK" printed on them.

  • Zenith Z386SX-20, 8MB FPM, Video 7 1024i, Unhoused
  • AOpen AP43, Am5x86-133@160, 1MB L2, 128MB FPM, Stealth III S540 32MB Savage4, SB32
  • ITX-Llama, 3Dfx V3
  • Asus CUV4X-E, P3-933, 512MB PC133, Hercules 3D Prophet II MX 32MB, SB Live!

Reply 19 of 21, by rasz_pl

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OMG this threat, first half is like OP talking to chatbots 😁

Cant really check if inserted ram is EDO in a purely software way. You need BIOS assistance - BIOS will first switch memory controller to EDO mode when detecting ram, failing that downgrade to FPM and run ram detection again. Then you can check if memory controller is running in EDO mode EDO or fastpage ram?

Last edited by rasz_pl on 2024-09-25, 21:37. Edited 1 time in total.

https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
https://github.com/raszpl/440BX Reference Design adapted to Kicad
https://github.com/raszpl/Zenith_ZBIOS MFM-300 Monitor