Low versus High density SDRAM

[John Henriksen]

Does anyone know of a good reference for learning about the difference
between low and high density SDRAM. I just got a 256M PC-133 stick
that is only detecting as 128M. After a little searching, I found
references to high and low density, but I can't find a good resource
to learn more about it.

Thanks for any information!

 

[Roger Hunt]

Does anyone know of a good reference for learning about the difference
between low and high density SDRAM. I just got a 256M PC-133 stick
that is only detecting as 128M. After a little searching, I found
references to high and low density, but I can't find a good resource
to learn more about it.

It's the length of each memory address isn't it?
AIUI old motherboards are a bit myopic and can only see half way down.

 

[The little lost angel]

Does anyone know of a good reference for learning about the difference
between low and high density SDRAM. I just got a 256M PC-133 stick
that is only detecting as 128M. After a little searching, I found
references to high and low density, but I can't find a good resource
to learn more about it.

There should be some relevant docs on Kingston or Crucial websites.

But the brief of it is, low/hi is all relative to when/what you're
talking about. They used to make 256MB DIMM with say 128Mbits density
chips, this will require 8 chips on each side of the DIMM to make a
double sided 256MB DIMM with 16chips. Now they got 256Mbits and you
can get the same 256MB with a single sided 8 chip DIMM.

Relatively speaking, the older 256MB uses low density chips compared
to the newer ones. So if your motherboard only supports 128MBits chip,
it won't see the other bits and you get half.

Hmm, one warning though, I'm the village idiot here so I might be
quite wrong... as evident by the time daytripper(or somebody) banged
his head against the wall in despair pPpp

--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[Tony Hill]

There should be some relevant docs on Kingston or Crucial websites.

But the brief of it is, low/hi is all relative to when/what you're
talking about. They used to make 256MB DIMM with say 128Mbits density
chips, this will require 8 chips on each side of the DIMM to make a
double sided 256MB DIMM with 16chips. Now they got 256Mbits and you
can get the same 256MB with a single sided 8 chip DIMM.

Relatively speaking, the older 256MB uses low density chips compared
to the newer ones. So if your motherboard only supports 128MBits chip,
it won't see the other bits and you get half.

Hmm, one warning though, I'm the village idiot here so I might be
quite wrong... as evident by the time daytripper(or somebody) banged
his head against the wall in despair pPpp

Haha! L.Angel, you give yourself far too little credit!

You are, of course, bang-on with this one, and I would be pretty darn
certain that you're example is exactly what John in running into.

 

[John Henriksen]

Haha! L.Angel, you give yourself far too little credit!

You are, of course, bang-on with this one, and I would be pretty darn
certain that you're example is exactly what John in running into.

Except, I have 2 modules...both using 16x8 (128Mbit) chips. One is
seen in my mobo as 256, the other as 128. I think I have tracked down
the problem though, and that is simply that this mobo I am using to
test is just too old. I checked it's specs (AOpen AX59Pro) and it says
it can use SDRAM...but doesn't even list PC-66... I assume this means
it was before SDRAM got speed designations, therefore, it requires
early SDRAM technology.

Both of these sticks I'm testing are PC-133, so even though I have
low-density RAM, I believe I'm just running into a compatibility
problem now.

I'll see if I can't track down a middle-aged mobo the requires
low-density PC-100 or PC-133 RAM to test these sticks on.

Thanks for the answers all!

 

[daytripper]

There should be some relevant docs on Kingston or Crucial websites.

But the brief of it is, low/hi is all relative to when/what you're
talking about. They used to make 256MB DIMM with say 128Mbits density
chips, this will require 8 chips on each side of the DIMM to make a
double sided 256MB DIMM with 16chips. Now they got 256Mbits and you
can get the same 256MB with a single sided 8 chip DIMM.

Relatively speaking, the older 256MB uses low density chips compared
to the newer ones. So if your motherboard only supports 128MBits chip,
it won't see the other bits and you get half.

Hmm, one warning though, I'm the village idiot here so I might be
quite wrong... as evident by the time daytripper(or somebody) banged
his head against the wall in despair pPpp

The whole "high vs low density" thing - just like the "single sided vs double
sided" thing - is decidedly not worth head-banging. Battling the dark forces
of the Air Transportation Industry - now *that's* worth a good head-banging!

In any case, you forgot to discuss "x4 vs x8" in your thesis.
Sorry.

/daytripper ;-)