Memory: Crucial specs

BTW, I forgot to offer thanks for any help with these questions and
those in the prior two threads. I know it's not "required", but
still.

Memory: Crucial specs

Things are fine now, except for whatever my first thread tonight
brings up, but for a while I was worried I had wasted money buying the
wrong RAM.

During my troubles in the previous two threads, I suddenly had the
fear that I had not followed Paul's advice diligently enough. I
coudln't remember the details of what I'd done.

That is, I intended to but had I really made sure to buy low-density?

I found the ad for the memory I bought and it clearly said "low
density", but he could be wrong. Before I bought, I had looked up the
RAM on the Crucial webpage, and I didn't notice at the time that
strangely, it doesn't say what the density is.
1) Isn't that pretty sloppy of them? Incredibly bad?
http://www.crucial.com/store/partspe...le=CT12864Z335

Then I googled the part number and found other people asking the same
question about the same part.

***** 2) Is it true what someone said that if there are 16 chips on
the stick, it is low density? (Is that because with high density, all
the RAM could be squeezed into 8 chips?)

A question with a non-answer by Crucial:
http://www.forums.crucial.com/t5/Sta...ity/td-p/18386

3)
http://www.amazon.com/Crucial-Techno.../dp/B0002IP2TY
"33 of 35 people found the following review helpful:
1.0 out of 5 stars Be Warned, August 18, 2008
By Netadmin - See all my reviews
This review is from: Crucial Technology CT12864Z335 1GB 184-Pin PC2700
333Mhz DIMM DDR RAM Memory (Electronics)
1 star our of 5. Nothing in the description indicates this is high
density memory and will not work in 90% of the older computers out
there that need low density memory.

I used the configurator at Crucial and it correctly told me the type
of memory I needed but it cost twice as much as the memory here.
Thinking that Crucial was trying to rip me off I bought the memory
listed on this page only to find it did not work. Turns out Crucial
was trying to steer me straight not rip me off. Don't make the same
mistake I did and think just because it says 1GB 184-Pin PC2700 333Mhz
DIMM DDR RAM that is all you need to know to match it correctly to
your PC. "

OTOH, two other people loved it.

I kept looking and found one page with a bunch of stores that sell
CT12864Z335, and so far none say whether it is low density or not,
maybe because they are relying on the Crucial page for info?
http://www.shopwiki.com/_1GB+333MHZ+...+-+CT12864Z335

OTOH, here's a webpage that maybe sells only low-density memory!
(At least I suppose they mark it if it's not.)
http://low-density.memorycheap.us/10...AM_Memory.html
And it does list it. But they might be wrong too. Why doesn't
Crucial say?

mm wrote:
> BTW, I forgot to offer thanks for any help with these questions and
> those in the prior two threads. I know it's not "required", but
> still.
>
> Memory: Crucial specs
>
> Things are fine now, except for whatever my first thread tonight
> brings up, but for a while I was worried I had wasted money buying the
> wrong RAM.
>
> During my troubles in the previous two threads, I suddenly had the
> fear that I had not followed Paul's advice diligently enough. I
> coudln't remember the details of what I'd done.
>
> That is, I intended to but had I really made sure to buy low-density?
>
> I found the ad for the memory I bought and it clearly said "low
> density", but he could be wrong. Before I bought, I had looked up the
> RAM on the Crucial webpage, and I didn't notice at the time that
> strangely, it doesn't say what the density is.
> 1) Isn't that pretty sloppy of them? Incredibly bad?
> http://www.crucial.com/store/partspe...le=CT12864Z335
>
> Then I googled the part number and found other people asking the same
> question about the same part.
>
> ***** 2) Is it true what someone said that if there are 16 chips on
> the stick, it is low density? (Is that because with high density, all
> the RAM could be squeezed into 8 chips?)
>
> A question with a non-answer by Crucial:
> http://www.forums.crucial.com/t5/Sta...ity/td-p/18386
>
> 3)
> http://www.amazon.com/Crucial-Techno.../dp/B0002IP2TY
> "33 of 35 people found the following review helpful:
> 1.0 out of 5 stars Be Warned, August 18, 2008
> By Netadmin - See all my reviews
> This review is from: Crucial Technology CT12864Z335 1GB 184-Pin PC2700
> 333Mhz DIMM DDR RAM Memory (Electronics)
> 1 star our of 5. Nothing in the description indicates this is high
> density memory and will not work in 90% of the older computers out
> there that need low density memory.
>
> I used the configurator at Crucial and it correctly told me the type
> of memory I needed but it cost twice as much as the memory here.
> Thinking that Crucial was trying to rip me off I bought the memory
> listed on this page only to find it did not work. Turns out Crucial
> was trying to steer me straight not rip me off. Don't make the same
> mistake I did and think just because it says 1GB 184-Pin PC2700 333Mhz
> DIMM DDR RAM that is all you need to know to match it correctly to
> your PC. "
>
> OTOH, two other people loved it.
>
> I kept looking and found one page with a bunch of stores that sell
> CT12864Z335, and so far none say whether it is low density or not,
> maybe because they are relying on the Crucial page for info?
> http://www.shopwiki.com/_1GB+333MHZ+...+-+CT12864Z335
>
> OTOH, here's a webpage that maybe sells only low-density memory!
> (At least I suppose they mark it if it's not.)
> http://low-density.memorycheap.us/10...AM_Memory.html
> And it does list it. But they might be wrong too. Why doesn't
> Crucial say?

An alternate way of determining density, is to use the markings
on the module.

http://img.systemaxdev.com/productme...1/134916-1.jpg

CT12864Z335.16TFY <--- The Crucial sticker

It's possible the 16TFY would be a giveaway. The 16 part is
used to detect double sided memory (8 chipset per side). I don't
have a table that says what TFY stands for. (It might even be
the chip revision used.)

To zero in on the Micron sticker, I used the Micron UDIMM table,
matching part numbers against what I could read on the label.
My conclusion is, it's likely this one.

Micron MT16VDDT12864AY-335F2 <--- The Micron (parent company) sticker
PC2700U-25331-Z

http://www.micron.com/partscatalog.h..._modules/udimm

http://cache.micron.com/Protected/ex...28_256x64A.pdf

On page 2 of the DD16C64_128_256x64A.pdf document, middle column
corresponds to the 1GB UDIMM.

"Parameter 1GB

Device configuration 512Mb (64 Meg x 8)"

The alternatives are 64Mx8 (low density) and 128Mx4 (high density). So the
Micron datasheet says it's low density.

You can also contact Crucial pre-sales, and the staff there can help
you with issues like this.

Paul

On Thu, 16 Dec 2010 03:19:23 -0500, Paul <> wrote:

>mm wrote:
>> BTW, I forgot to offer thanks for any help with these questions and
>> those in the prior two threads. I know it's not "required", but
>> still.
>> .....
>> I kept looking and found one page with a bunch of stores that sell
>> CT12864Z335, and so far none say whether it is low density or not,
>> maybe because they are relying on the Crucial page for info?
>> http://www.shopwiki.com/_1GB+333MHZ+...+-+CT12864Z335
>>
>> OTOH, here's a webpage that maybe sells only low-density memory!
>> (At least I suppose they mark it if it's not.)
>> http://low-density.memorycheap.us/10...AM_Memory.html
>> And it does list it. But they might be wrong too. Why doesn't
>> Crucial say?
>
>An alternate way of determining density, is to use the markings
>on the module.
>
>http://img.systemaxdev.com/productme...1/134916-1.jpg
>
> CT12864Z335.16TFY <--- The Crucial sticker
>
> It's possible the 16TFY would be a giveaway. The 16 part is
> used to detect double sided memory (8 chipset per side).

So are you saying that if there are 16 chips, it's low density?

OT:
I like this line from wikip: "In the past, registered memory was
called buffered memory and unregistered memory was called unbuffered
memory. Registered memory got renamed in common use, but unbuffered
memory did not."

> I don't
> have a table that says what TFY stands for. (It might even be
> the chip revision used.)
>
> To zero in on the Micron sticker, I used the Micron UDIMM table,
> matching part numbers against what I could read on the label.
> My conclusion is, it's likely this one.
>
> Micron MT16VDDT12864AY-335F2 <--- The Micron (parent company) sticker
> PC2700U-25331-Z
>
> http://www.micron.com/partscatalog.h..._modules/udimm
>
> http://cache.micron.com/Protected/ex...28_256x64A.pdf

This one expired by the time I looked at it, but I found
http://www.micron.com/products/Produ...DDT12864AY-335
for the same DDR, MT16VDDT12864AY-335F2, and it too, for
specifications, says:
Density: 1GB
Technology: DDR SDRAM
RoHS: Yes
Part Status: EOL Pending
Comp. Count: 16
Depth: 128Mb
Width: x64
Pin Count: 184-pin
Op. Temp.: 0C to +70C
Data Rate: 333 MT/s
Speed: PC2700
CL: CL = 2.5
Voltage: 2.5V
Comp. Config: 64 Meg x 8
ECC: Non ECC
Module Ranks: Dual Rank

They really make it hard.

> On page 2 of the DD16C64_128_256x64A.pdf document, middle column
> corresponds to the 1GB UDIMM.
>
> "Parameter 1GB
>
> Device configuration 512Mb (64 Meg x 8)"
>
>The alternatives are 64Mx8 (low density) and 128Mx4 (high density). So the
>Micron datasheet says it's low density.

Wow. It shouldn't be this much effort, should it?

>You can also contact Crucial pre-sales, and the staff there can help
>you with issues like this.

Well, there was a question about this very item, answered by a Crucial
employee, but he didn't actually answer the question! If he added
that last line that you included, it would have been clear and I
wouldn't have posted.

http://www.forums.crucial.com/t5/Sta...ity/td-p/18386
09-04-2010 06:38 PM
Can someone advise me if the above mentioned Crucial part no 1GB
PC2700 DIMM is low density or high density ? TIA. (476 Views)

Reply 09-08-2010 10:15 AM
Hello,
All Crucial 1GB unbuffered non-ECC DDR modules are going to be 16-chip
modules. These parts are made up from 512Mb components.
Dude, Crucial Employee, US Registered: 03-08-2010

More importantly, either the listing for each stick should include
this info, or at least somewhere prominent on the webpage it should
say that "All Crucial 1GB unbuffered non-ECC DDR modules are going to
be 16-chip modules, low-density." I should write them and tell them
this.

> Paul

mm wrote:
> On Thu, 16 Dec 2010 03:19:23 -0500, Paul <> wrote:
>
>> mm wrote:
>>> BTW, I forgot to offer thanks for any help with these questions and
>>> those in the prior two threads. I know it's not "required", but
>>> still.
>>> .....
>>> I kept looking and found one page with a bunch of stores that sell
>>> CT12864Z335, and so far none say whether it is low density or not,
>>> maybe because they are relying on the Crucial page for info?
>>> http://www.shopwiki.com/_1GB+333MHZ+...+-+CT12864Z335
>>>
>>> OTOH, here's a webpage that maybe sells only low-density memory!
>>> (At least I suppose they mark it if it's not.)
>>> http://low-density.memorycheap.us/10...AM_Memory.html
>>> And it does list it. But they might be wrong too. Why doesn't
>>> Crucial say?
>> An alternate way of determining density, is to use the markings
>> on the module.
>>
>> http://img.systemaxdev.com/productme...1/134916-1.jpg
>>
>> CT12864Z335.16TFY <--- The Crucial sticker
>>
>> It's possible the 16TFY would be a giveaway. The 16 part is
>> used to detect double sided memory (8 chipset per side).
>
> So are you saying that if there are 16 chips, it's low density?
>
> OT:
> I like this line from wikip: "In the past, registered memory was
> called buffered memory and unregistered memory was called unbuffered
> memory. Registered memory got renamed in common use, but unbuffered
> memory did not."
>
>> I don't
>> have a table that says what TFY stands for. (It might even be
>> the chip revision used.)
>>
>> To zero in on the Micron sticker, I used the Micron UDIMM table,
>> matching part numbers against what I could read on the label.
>> My conclusion is, it's likely this one.
>>
>> Micron MT16VDDT12864AY-335F2 <--- The Micron (parent company) sticker
>> PC2700U-25331-Z
>>
>> http://www.micron.com/partscatalog.h..._modules/udimm
>>
>> http://cache.micron.com/Protected/ex...28_256x64A.pdf
>
> This one expired by the time I looked at it, but I found
> http://www.micron.com/products/Produ...DDT12864AY-335
> for the same DDR, MT16VDDT12864AY-335F2, and it too, for
> specifications, says:
> Density: 1GB
> Technology: DDR SDRAM
> RoHS: Yes
> Part Status: EOL Pending
> Comp. Count: 16
> Depth: 128Mb
> Width: x64
> Pin Count: 184-pin
> Op. Temp.: 0C to +70C
> Data Rate: 333 MT/s
> Speed: PC2700
> CL: CL = 2.5
> Voltage: 2.5V
> Comp. Config: 64 Meg x 8
> ECC: Non ECC
> Module Ranks: Dual Rank
>
> They really make it hard.
>
>> On page 2 of the DD16C64_128_256x64A.pdf document, middle column
>> corresponds to the 1GB UDIMM.
>>
>> "Parameter 1GB
>>
>> Device configuration 512Mb (64 Meg x 8)"
>>
>> The alternatives are 64Mx8 (low density) and 128Mx4 (high density). So the
>> Micron datasheet says it's low density.
>
> Wow. It shouldn't be this much effort, should it?
>
>> You can also contact Crucial pre-sales, and the staff there can help
>> you with issues like this.
>
> Well, there was a question about this very item, answered by a Crucial
> employee, but he didn't actually answer the question! If he added
> that last line that you included, it would have been clear and I
> wouldn't have posted.
>
> http://www.forums.crucial.com/t5/Sta...ity/td-p/18386
> 09-04-2010 06:38 PM
> Can someone advise me if the above mentioned Crucial part no 1GB
> PC2700 DIMM is low density or high density ? TIA. (476 Views)
>
> Reply 09-08-2010 10:15 AM
> Hello,
> All Crucial 1GB unbuffered non-ECC DDR modules are going to be 16-chip
> modules. These parts are made up from 512Mb components.
> Dude, Crucial Employee, US Registered: 03-08-2010
>
> More importantly, either the listing for each stick should include
> this info, or at least somewhere prominent on the webpage it should
> say that "All Crucial 1GB unbuffered non-ECC DDR modules are going to
> be 16-chip modules, low-density." I should write them and tell them
> this.
>
>> Paul
>

First off, high density isn't a very precise term, and it's a substitute
for saying "hey, you bought bad RAM". There is more than one situation
termed high density.

In this case, the high density and low density modules both use sixteen
chips. The low density module uses (16) 64Mx8, and the high density uses
(16) 128Mx4. A "rank" of memory, is enough memory chips to make a 64 bit
wide array. In the case of the high density UDIMM, all sixteen chips
are used to make one rank. So when that high density module is accessed,
all sixteen chips respond at the same time.

In the low density module case, there are two (8) 64Mx8 ranks. When
the low density UDIMM is accessed, either eight chips on one side
of the module, or eight chips on the other side of the module, respond.
So one half of the module "sleeps", for want of a better word. It means
there are two sets of control signals. One set of signals per side, with
eight loads on each signal.

So this information, is what I seek. The chip dimensions are
what is important. If you look at some Intel desktop chipset datasheets,
the preferred chip widths are x8 and x16, while x4 is not mentioned.
Most of the time, end users are using the x8 chips, to get the
highest possible module density. If you go with x4, that's not
even on Intel's radar.

"Parameter 1GB

Device configuration 512Mb (64 Meg x 8)"

That "x8" tells me I got the good stuff.

*******

Another one of the cases for RAM, would be something like
(16) 32Mx8 versus (8) 64Mx8. In that case, the issue is some
motherboards only detecting half of the memory array. Some
chipsets would lack enough address bits to access the entire
64M range. And the result, is only half the memory is detected.
In that case, a sticker with "-8" or "-16", would be
enough info to tell the difference. Both modules use 8 chip
ranks. The preferred module in that case, is the 16 chip one,
because the chips "aren't as deep" and only span 32M.

So you can see in the notation "(16) 32Mx8", there are three
numbers they can play with. One kind of high density, affects
different numbers, than the other kind of high density case.
And one can be detected by chip count, while the other, you
may want to get an actual chip part number, to verify the
device width.

Paul