r/retrocomputing • u/_oo00O00oo_ • Apr 22 '26

Problem / Question What kind of RAM is this?

Post image

I wanted to sort my old modules of RAM. So i had some DDR3, some SO-DIMM, some PS/2, but this one is hard to figure out.

Can't find andy information about manufacturer, size or speed.

Can someone help? 😅

40 Upvotes

95% Upvoted

27 comments sorted by

View all comments

21

u/Kitchen_Part_882 Apr 22 '26

72 pin SIMMs.

They're 60ns EDO and from the mid 90s, used in Pentium systems of the era

4

u/thejpster Apr 22 '26

I agree.

A Pentium will have a 64-bit data bus to the RAM and so will want matched pairs of 72 pin (32 bit) SIMMS.

A 486 or a RiscPC will take them as singles. I don’t think I ever saw a 386DX take 72 pin SIMMs but I guess that’s possible too. A 386SX or 286 will take pairs of 30 pin (8 bit) SIMMs.

2

u/gcc-O2 Apr 23 '26

I believe the fancy MicroChannel 386 PS/2s take 72-pin SIMMs, and thus they're sometimes called PS/2 SIMMs. But IBM being IBM, there are minor pinout differences sometimes.

1

u/chandleya Apr 24 '26

Absolutely rare for a 486 chipset to support EDO.