if it makes you feel better, I had a dell pentium 2 server that had similar double stacked modules. I looked in my spare memory box and it would seem that I don't have it anymore. 🙁

Isn't this the precursor to that 3D memory cluster thing IBM and Micron are collaborating on?

Logistics wrote:

Isn't this the precursor to that 3D memory cluster thing IBM and Micron are collaborating on?

its standard pc100 ecc/registerd ram. instead of making 512k chips they decided to use up their old 256k chips by double stacking them.

ECC unbuffered

That's wrong... those are buffered (a.k.a., registered) modules. I'd be amazed if a SS7 board will accept them.

And yeah, the double stacking was just a way of getting more chips onto a DIMM without making it 3" tall (though there were some double-height modules made too, which look equally strange). There was all sorts of weird server memory back in the late '90s. Somewhere around here I have some double-stacked PC100R DIMMs with built-in heatspreaders, and even one triple-stacked DIMM.

As a matter of fact, they're buffered. I bought them from eBay and the seller clearly stated "unregistered ECC" memory module.

They're marked KTD-PC100X72RC3/256I 9852222-002.A00 so they should be made by Kingston but I've been unable to find any datasheet about them.

I think KTD is the prefix Kingston used for memory they made for Dell. I know KTC is Compaq and KTM is IBM.
This page
http://www.allquests.com/question/1923128/upd … redge-1300.html
if it's accurate, lists that part number for Dell PowerEdge 1300, 2300, 4300, 4350. But really it would work on anything with an appropriate chipset.

A few years ago I bought a bulk listing of about 100-150 memory modules, most of them were 36-chip 256MB PC100 Registered ECC. Many of them look like these. Some have dual PCBs soldered together, some are connected by ribbon cables (!) but usually the chips are directly piggybacked on each other (which is hard to tell without looking close).

I doubt any of the super 7 chipsets support registered memory, but I'm not sure.
I imagine these were mostly used with 440BX/440GX workstations and servers, but a 440BX desktop will work just as well. That's what they would be most useful with. I think a VIA KT133 (Athlon) or 694X (P3) chipset will also take them but I'm not sure. Being PC100 reduces their usefulness with those.

At the time these were made, I'm guessing they had to use 4-bit chips to get the size they wanted. The use of 4-bit chips is JEDEC legit with registered memory and it's allowed by the 440BX and 440GX specs, and probably any other registered memory chipset. However, it's not allowed for unbuffered memory, and there was some shoddy no-name memory that broke that rule.
Yours is registered though, so it's not doing anything wrong other than not being what the seller advertised.

My 440GX HP Kayak actually requires stacked memory to achieve 512MB per DIMM. It took me years to figure that out. I ordered a module from Crucial which was guaranteed compatible, but it didn't work. It was a typical 18-chip module with 8-bit chips. It met the chipset specs but even the latest version of HPs broke-ass BIOS wouldn't take it. It would count the memory at POST, but as soon as it handed off to the operating system, it would give an ECC error. A replacement did the same thing.
Because of the BIOS, it HAD to have the older modules with 36 4-bit chips. And those were too tall, so I mangled the insides to make one of them fit. I couldn't figure out what HP was thinking.
Much later I finally realized the existence of these stacked modules that aren't double-tall. That's the only type of 512MB module that will both work and physically fit.

shamino wrote:

I think KTD is the prefix Kingston used for memory they made for Dell. I know KTC is Compaq and KTM is IBM. This page http://ww […]
Show full quote

They're marked KTD-PC100X72RC3/256I 9852222-002.A00 so they should be made by Kingston but I've been unable to find any datasheet about them.

I think KTD is the prefix Kingston used for memory they made for Dell. I know KTC is Compaq and KTM is IBM.
This page
http://www.allquests.com/question/1923128/upd … redge-1300.html
if it's accurate, lists that part number for Dell PowerEdge 1300, 2300, 4300, 4350. But really it would work on anything with an appropriate chipset.

A few years ago I bought a bulk listing of about 100-150 memory modules, most of them were 36-chip 256MB PC100 Registered ECC. Many of them look like these. Some have dual PCBs soldered together, some are connected by ribbon cables (!) but usually the chips are directly piggybacked on each other (which is hard to tell without looking close).

I doubt any of the super 7 chipsets support registered memory, but I'm not sure.
I imagine these were mostly used with 440BX/440GX workstations and servers, but a 440BX desktop will work just as well. That's what they would be most useful with. I think a VIA KT133 (Athlon) or 694X (P3) chipset will also take them but I'm not sure. Being PC100 reduces their usefulness with those.

At the time these were made, I'm guessing they had to use 4-bit chips to get the size they wanted. The use of 4-bit chips is JEDEC legit with registered memory and it's allowed by the 440BX and 440GX specs, and probably any other registered memory chipset. However, it's not allowed for unbuffered memory, and there was some shoddy no-name memory that broke that rule.
Yours is registered though, so it's not doing anything wrong other than not being what the seller advertised.

My 440GX HP Kayak actually requires stacked memory to achieve 512MB per DIMM. It took me years to figure that out. I ordered a module from Crucial which was guaranteed compatible, but it didn't work. It was a typical 18-chip module with 8-bit chips. It met the chipset specs but even the latest version of HPs broke-ass BIOS wouldn't take it. It would count the memory at POST, but as soon as it handed off to the operating system, it would give an ECC error. A replacement did the same thing.
Because of the BIOS, it HAD to have the older modules with 36 4-bit chips. And those were too tall, so I mangled the insides to make one of them fit. I couldn't figure out what HP was thinking.
Much later I finally realized the existence of these stacked modules that aren't double-tall. That's the only type of 512MB module that will both work and physically fit.

Damn, I've been wanting one of those HP Kayak machines for a while. What are the fastest Xeons one of those will run?

shamino, awesome informing post, thank you very much: you honor the name of the hero of Sosaria 😉

m1919 wrote:

Damn, I've been wanting one of those HP Kayak machines for a while. What are the fastest Xeons one of those will run?

Sorry, I was out of town for several days.
The model is a Kayak XW 6/450. It came with a Xeon 450, I added a 2nd of those afterward. I've never tried anything faster.
I vaguely think I remember that they can run Katmai based Xeons, but it's been a long time since I researched that so I could be remembering wrong. I'm not even sure those exist, but I guess they do. 😀
A long time ago I tried to find out if it could run a Coppermine based Xeon, but I couldn't find much info about it. One post I found from somebody said that they had been able to run a single Coppermine at something like 800MHz, but with 2 of them installed something didn't work right.
It has replaceable VRMs so voltage support shouldn't be a problem, but the BIOS is another story.

Considering that HP never bothered to fix the BIOS support for 32Mx8 style 512MB modules, I doubt they bothered to specifically support Coppermines either. If they do work then there's probably quirks, but I've never had a slot-2 Coppermine to test for myself.

I originally used that Kayak as my main PC, and it's surely the most bulletproof PC I ever had. But I get the impression it's a model that HP forgot about the day after they shipped it.