Come on, no one has an answer to this? 😵

Photo compared to a 30-pin?

I actually remember this back from the 90s, I once got 32 pin ram and I remember my friend telling me it works fine in 30 pin slots and it did, it was a tighter fit but I was able to put it in. Apart from that no explanation

Found a photo of one. Traces do go... somewhere. Maybe there was some propietary motherboard that had some signals connected to those extra pins instead of standard locations and therefore "required" 32-pin simms.

I have never seen one but there is edram for dca architecture direct cache access, where the cache is on the ram chip not on the motherboard, maybe this is one

treeman wrote:

I have never seen one but there is edram for dca architecture direct cache access, where the cache is on the ram chip not on the motherboard, maybe this is one

At least on SIMM's on that photo those are bog standard DRAM chips. What I could find about edram mentioned just 72-pin simms.

I found this old thread from usenet in google groups: https://groups.google.com/d/msg/comp.os.ms-wi … Nk/Cfinvs7gl-cJ

Curt wrote:

Some "almost standard" PC's use them...my guess was to force buyers to
buy special memory at a premium price. Unisys PC's had 32 pin memory.

Steve Austin wrote:

32 pins SIMMs were also made to get around a patent 2 of the pins do not
connect to anything.

that does sound right, I do remember putting in 32pin chip in a 30pin slot, it did feel like I was forcing it in but the pc booted up and detected the extra memory.... some 20 years ago when I was in highschool

On these modules the extra pins do not seem to connect anywhere (they might have a connection to internal ground or V+ planes)

32pin Simms could be double sided
30 are always single

rmay635703 wrote on 2019-07-19, 02:38:

32pin Simms could be double sided
30 are always single

You're wrong. This 512KB RAM is 30 (above)

He probably meant double-banked, which would require at least one additional signal. Most people say double-sided instead when they really mean double-banked. One is (physical) layout of the chips, the other one is organisation. There's no dependency between the both.

RiP wrote on 2020-02-27, 11:43:

rmay635703 wrote on 2019-07-19, 02:38:

32pin Simms could be double sided
30 are always single

You're wrong. This 512KB RAM is 30 (above)

Just an FYI, poster above is speaking truth

Also...
Notice the # 32 printed right in the photo of the “30 pin” simm?

In the day I remember companies advertising 30 pin and 32 pin Simms and both look the same to me.

Also I stated using the word COULD not had to be.

appiah4 wrote on 2019-07-14, 22:50:

They seem to work 100% fine in a 30-pin slot, though.

Unfortunately it was not so in my case.

Those 32-pin SIMM were given by a friend of mine who wasn't sure what type of computer he retired them from. I tried them on my Am486DX2-50 and it couldn't POST, gave me beeping error.

Searched the web many times and this thread seems to be the only valid discussion on 32-pin SIMM; the AnandTech page ("Boasting twice the bandwidth of a 32 pin SIMM") is more likely a typo.

Since posting these I camw into possession of 8 more 32 pin 256KB SIMMs and they came on a 386 mainboard where they work peefectly fine.

To this day I still don't quite know or understand the two extra pins..

any chance of a pinout? continuity measurement between pads & chip pins.