The Classic Geek: Help Me Identify These Rambus Style Mystery SDRAM Modules (Identified!)

Can anyone help me identify who made these SDRAM modules?

My retro-tech adventures, specifically my recent Windows 95 based retro gaming build using nothing by the very first ITX motherboard, the EPIA-800, lead me to discover a strange style of SDRAM I’ve never seen before. While browsing eBay, I ran across a 512MB PC133 SDRAM kit (2x256MB) that had attached heat spreaders and bought them just because I had never seen them before. While that may be a common site today, it wasn’t back in the SDRAM days, that trend didn’t really take off until well into the DDR years, at least not here in the US.

In fact, the only RAM sticks I had ever seen that had heat spreaders on them like this were RDRAM modules, better known as Rambus memory (the company that made it). I’m not going to cover any specifics about RDRAM, but there is a decent article over on Wikipedia you can read if you’re interested. Basically, it was a competitor to the standard SDRAM we’re all familiar with.

Wikipedia Article: https://en.wikipedia.org/wiki/RDRAM

Most people will have never seen or used RDRAM, but many people did have it in their homes, they just didn’t know it. RDRAM was the type of RAM used in the Nintendo 64. Remember the memory expansion module you could buy for the N64, and the “jumper pack” that had to be in the unit for it function without the memory expansion? That was there due to a quirk in how RDRAM worked, they had to be installed in pairs and you could not have any empty slots, you had to use a “dummy” to terminate the memory lanes. The N64’s jumper pack was the terminator dummy for its RDRAM.

The other thing about RDRAM was it got much warmer than SDRAM, so it almost always had a heat spreader or heatsink to keep it cool. If you look inside an old N64 for example, the RDRAM modules are under a heatsink, as are the ones in the memory expansion. In short, the heat spreader was actually there for a useful reason. With standard SDRAM, which ran much cooler, there was no need for extra heat dissipation, so you never saw heat spreaders on SDRAM.

Apparently, at some point, someone decided to manufacture SDRAM that used the same heat spreaders as RDRAM modules, purely for cosmetics I assume. These sticks of RAM had to use a custom PCB to get the rivet holes to line up because those holes didn’t exist on standard SDRAM sticks, so it was no small task to produce and I assume it had to be done by a known manufacturer of the time. However, no matter how much digging around on the net I do, I can’t seem to identify who made these RAM sticks.

I’ve managed to find them listed for sale, or posted about on forums, in green, blue, and gold colors as of the writing of this article. All of them have the same slanted “M” logo, but none of the identifying numbers on the sticks, or the chips inside, indicate who made them.

At first, I thought maybe the “M” logo was an old Micron logo, but I can’t see any point they used anything but their standard “M” with an oval line around it. In fact, I can’t find any memory manufactures from that era that used that slanted “M” logo. Then again, I found a single German eBay listing referring to this as Micron RAM, seen below.

I spent quite a bit of time digging through Google Images and image recognition, forums, and the Wayback Machine with no luck. Every single time I find them mentioned anywhere, they always label them as “unbranded”. So, I decided to write this short article and post it around and see if, by sheer luck, someone may see it and recognize the logo or the memory modules themselves and help me shed light on this mystery.

Rambus lost out to standard SDRAM, so did Micron, or whoever made these, have leftover stock of the RDRAM heat spreaders to use up and decided to dress up some SDRAM with them? It's just a guess.

I’ve included links to a couple places I found these modules listed or talked about, just in case you’re interested.

https://goughlui.com/2016/01/17/tech-flashback-my-collection-of-sdram-256mb-512mb-modules/

https://www.techpowerup.com/forums/threads/tpus-nostalgic-hardware-club.108251/page-314

If you’ve seen these before, or have any idea who may have manufactured them, either post it here in the comment section below, or on the forum or website where I linked to this article. I’ll be checking them from time to time and update this article when, and if, I get any new information. References and links would be great if you have any!

Thanks for reading!

** EDIT: March 2024 **

The mystery has been solved!

Thanks to a random post over on Vogons, someone was able to ID the logo for me and point me to a company called "Celetronix", where I was able to see they were the source of these SDRAM modules with heat spreaders. As seen in the screenshot below, they were being sold in the early 2000's for about $30 to $40 each, depending on capacity.

There are actually a few companies associated with Celetronix, all long since defunct it seems. If you want to take a trip down memory lane (pun intended), all the info I've found is linked below!