You say megabyte, I say mebibyte

[Grinder]

Consider this excerpt from the Intel D845HV/WN product guide:

| The boards supports system memory as defined below:
|
| • Up to three 168-pin SDRAM Dual Inline Memory Modules
| (DIMMs) with gold-plated contacts
|
| • PC133 SDRAM only
|
| • 64 Mbit, 128 Mbit, and 256 Mbit technologies for the
| following memory configurations:
| - 32 MB to 384 MB (64 Mbit technology)
| - Up to 768 MB (128 Mbit technology)
| - Up to 1.5 GB (256 Mbit technology)

I have a module with only these markings:

M111301A
32*64813MC16*8M133Mh

There's probably supposed to be a "z" on the end of that second line,
but the font is small and it fills the tiny sticker from edge to edge.
The module has 16 chips, 8 per side, and was purported to be 256MiB. It
shows up as 128MiB in the motherboard above.

From what's been said, I can guess that it's a "64 Mbit technology"
module, but how can I tell that from just an inspection of the unit?

This is a specific question, but I'm also interested in some background
on memory module density, as my current understanding is:

<Frankenstein>High density memory bad</Frankenstein>

 

[kony]

Consider this excerpt from the Intel D845HV/WN product guide:

| The boards supports system memory as defined below:
|
| • Up to three 168-pin SDRAM Dual Inline Memory Modules
| (DIMMs) with gold-plated contacts
|
| • PC133 SDRAM only
|
| • 64 Mbit, 128 Mbit, and 256 Mbit technologies for the
| following memory configurations:
| - 32 MB to 384 MB (64 Mbit technology)
| - Up to 768 MB (128 Mbit technology)
| - Up to 1.5 GB (256 Mbit technology)

I have a module with only these markings:

M111301A
32*64813MC16*8M133Mh

There's probably supposed to be a "z" on the end of that second line,
but the font is small and it fills the tiny sticker from edge to edge.
The module has 16 chips, 8 per side, and was purported to be 256MiB. It
shows up as 128MiB in the motherboard above.

When even the memory manufacturers themselves call capacity
megabit and megabyte, trying to declare you want it to be
mebibyte and then claiming megabyte means something else is
just a waste of time. The industry created the term to
apply to a specific value and it is not "you" or "me" that
has anything to say about it. A word can in fact mean
different things in different context. Giga, mega, do as
well when used with binary suffix in the computer field.
Even the hard drive manufacturers are wrong in their misuse
because the terms existed in the field before this segment
of the industry made and mislabled their drives' capacity.

 

[Paul]

Consider this excerpt from the Intel D845HV/WN product guide:

| The boards supports system memory as defined below:
|
| • Up to three 168-pin SDRAM Dual Inline Memory Modules
| (DIMMs) with gold-plated contacts
|
| • PC133 SDRAM only
|
| • 64 Mbit, 128 Mbit, and 256 Mbit technologies for the
| following memory configurations:
| - 32 MB to 384 MB (64 Mbit technology)
| - Up to 768 MB (128 Mbit technology)
| - Up to 1.5 GB (256 Mbit technology)

I have a module with only these markings:

M111301A
32*64813MC16*8M133Mh

There's probably supposed to be a "z" on the end of that second line,
but the font is small and it fills the tiny sticker from edge to edge.
The module has 16 chips, 8 per side, and was purported to be 256MiB. It
shows up as 128MiB in the motherboard above.

From what's been said, I can guess that it's a "64 Mbit technology"
module, but how can I tell that from just an inspection of the unit?

This is a specific question, but I'm also interested in some background
on memory module density, as my current understanding is:

<Frankenstein>High density memory bad</Frankenstein>

The table on page 23, extends even further than shown. There weren't
any large DIMMs to test when the board was released.

ftp://download.intel.com/support/motherboards/desktop/d845hv/A6513601.pdf

The 82845 three slot SDRAM based controller is here. Table 12 on
page 109, shows it can handle a 1GB SDRAM. Your 256MB should be
well away from any density issue. (I have 3x512MB on my 82845
based board, installed when it was new, and 1.5GB is reported.)

http://download.intel.com/design/chipsets/datashts/29072502.pdf

If you can boot a version of Windows that can run it, I'd try CPUZ.
It has a tab in the display for memory, and selecting the slot where
the particular stick is located, should dump info on it. If
nothing is displayed, it means there is no SPD chip (small, 8 pins or
less, serial PROM with speed and capacity info). Or it could mean
that CPUZ couldn't manage to find the SMBUS, to do the necessary
reads. That doesn't seem to get reported too often. so this should
be a good tool. At startup, be patient. It takes about
30 seconds on my current machine, before the CPUZ window appears.

http://www.cpuid.com/cpuz.php

The descriptive labels for memory, used in advertisements, are
not precise enough for figuring out what is going on. If you
really need to know, take the part number off the top of a
memory chip, and Google it. You may discover its base
capacity, like 16Mx8, and 16 of those would give 256MB.

The density issue has to do with available row and column
address bits, and comes into play when modules larger than
were intended, show up. On the 440BX, where 128MB DIMMs might
have been expected, you can run 256MB DIMMs if they are
"low density". If the 256MB DIMM had 16 chips, the number
of row/column is one less, than if the DIMM had 8 chips.
Each of the 8 chips would have double the amount of memory
("higher density") and need an extra address bit when
accessing the memory array inside. Failure to solve the density
issue, may result in only half the memory being detected. (BIOS
detects by attempted probes to memory, and some of the probes
failing due to the mismatch on addressing.)

An example of another chipset with a density issue, might be
an Nforce2. A 1GB with 16 chips (two banks), using 64Mx8 chips
would work properly. The "Ebay memory" config of 1GB DDR, which
is 16 chips (but only one bank), using 128Mx4 chips, is only
half detected. The "128M" dimensions in that case, require the
extra (missing) address bit. Note that this case doesn't work
like the one quoted for 440BX. In this case, both 1GB DDR have
16 chips, so unless the seller is honest and tells you there
are 128Mx4 chips being used, you'd actually have to get the
memory chip part number, to figure it out. (Nobody includes
the SPD table in a memory sales advertisement The
SPD contents, if you decoded them, would also be a dead
giveaway.)

Paul

 

[Grinder]

The table on page 23, extends even further than shown. There weren't
any large DIMMs to test when the board was released.

ftp://download.intel.com/support/motherboards/desktop/d845hv/A6513601.pdf

The 82845 three slot SDRAM based controller is here. Table 12 on
page 109, shows it can handle a 1GB SDRAM. Your 256MB should be
well away from any density issue. (I have 3x512MB on my 82845
based board, installed when it was new, and 1.5GB is reported.)

http://download.intel.com/design/chipsets/datashts/29072502.pdf

If you can boot a version of Windows that can run it, I'd try CPUZ.
It has a tab in the display for memory, and selecting the slot where
the particular stick is located, should dump info on it. If
nothing is displayed, it means there is no SPD chip (small, 8 pins or
less, serial PROM with speed and capacity info). Or it could mean
that CPUZ couldn't manage to find the SMBUS, to do the necessary
reads. That doesn't seem to get reported too often. so this should
be a good tool. At startup, be patient. It takes about
30 seconds on my current machine, before the CPUZ window appears.

CPU-Z 1.41 reports:

Memory tab

General frame
Type: SDRAM
Size: 256 MBytes
Bank Interleave: none

Timings frame
Frequency: 100.0 MHz
tCL: 3.0 clocks
tRCD: 3 clocks
tRP: 3 clocks
tRAS: 6 clocks

all other fields on this tab are disabled

SPD tab

only Slot #1 shows as populated, with SDRAM
Module Size: 128 MBytes
Max Bandwidth: PC133 (133 MHz)
Manufacturer: Samsung
Part Number: M366S1723BTS-C75
Serial Number: FFFFFFFF
Correction: None
Registered: no
Buffered: no
Week/Year: 255 / 255

Timings Table frame
Frequency: 133 MHz
tCL: 3.0
tRCD: 3
tRP: 3
tRAS: 6

- - - - - - - - - - - - - - - - -

How is it that my only memory module has a "Module Size" of 128 MBytes,
yet my system memory reports (and memtests) as 256 MBytes?

 

[Paul]

CPU-Z 1.41 reports:

Memory tab

General frame
Type: SDRAM
Size: 256 MBytes
Bank Interleave: none

Timings frame
Frequency: 100.0 MHz
tCL: 3.0 clocks
tRCD: 3 clocks
tRP: 3 clocks
tRAS: 6 clocks

all other fields on this tab are disabled

SPD tab

only Slot #1 shows as populated, with SDRAM
Module Size: 128 MBytes
Max Bandwidth: PC133 (133 MHz)
Manufacturer: Samsung
Part Number: M366S1723BTS-C75
Serial Number: FFFFFFFF
Correction: None
Registered: no
Buffered: no
Week/Year: 255 / 255

Timings Table frame
Frequency: 133 MHz
tCL: 3.0
tRCD: 3
tRP: 3
tRAS: 6

- - - - - - - - - - - - - - - - -

How is it that my only memory module has a "Module Size" of 128 MBytes,
yet my system memory reports (and memtests) as 256 MBytes?

Not a clue. I ran that part number, and the first hit says it is
a 128MB stick.

http://www.pinnaclemicro.com/frames/computer/parts.php?g=M366S1723BTS-C75&page=1

The actual Samsung site is hard to find stuff on. Not all the archived
pages work right. Again, that part number seems to be a 128MB, complete
with a typo for that particular entry (chip type and number are not
correct). One poster in Google with that part number, mentions the
RAM is single sided, so it is likely (8) 16Mx8. (I.e. Eight pieces
of 128Megabit technology.) Now, you say it has 16 chips, so something
isn't right. Maybe the module has the wrong SPD chip soldered to it ?

http://web.archive.org/web/20010709...emiconductors/search/datasheet.jsp?family=241

The chips themselves have part numbers on them, but my odds of finding
them on Samsung aren't very good. I was lucky that the above
archived page even rendered. Many of them do not.

Paul

 

[GT]

When even the memory manufacturers themselves call capacity
megabit and megabyte, trying to declare you want it to be
mebibyte and then claiming megabyte means something else is
just a waste of time. The industry created the term to
apply to a specific value and it is not "you" or "me" that
has anything to say about it. A word can in fact mean
different things in different context. Giga, mega, do as
well when used with binary suffix in the computer field.
Even the hard drive manufacturers are wrong in their misuse
because the terms existed in the field before this segment
of the industry made and mislabled their drives' capacity.

I must bite my tongue!

 

[GT]

When even the memory manufacturers themselves call capacity
megabit and megabyte, trying to declare you want it to be
mebibyte and then claiming megabyte means something else is
just a waste of time. The industry created the term to
apply to a specific value and it is not "you" or "me" that
has anything to say about it. A word can in fact mean
different things in different context. Giga, mega, do as
well when used with binary suffix in the computer field.
Even the hard drive manufacturers are wrong in their misuse
because the terms existed in the field before this segment
of the industry made and mislabled their drives' capacity.

Nope, I couldn't do it... Sorry Kony I have to argue again!

In the computing field, a network line rated at 1 megabit refers to
1,000,000 bits. So 8 megabits = 8,000,000 bits. There are 8 bits in a byte
so 8 megabits = 1 megabyte. Therefore 1 megabyte = 8,000,000 bits or
1,000,000 bytes. This agrees with the definition of mega, which is 1
million, or 10 to the power 6. There is no scientific definition of mega
where it means 1,024,000 - this is wrong. This definition of mega is widely
used (and dare I say accepted) by some in computing. There are even websites
that state mega = 1,024,000, or 2 to the power 10, but it is wrong. Mega is
a scientific, mathematical term meaning 10 to the power 6.

 

[kony]

Mega is
a scientific, mathematical term meaning 10 to the power 6.

.... and in the computer industry it is a different value
when referring to a binary value with byte or bit

Like I already wrote, terms can mean different things. Like
I already wrote, even the memory manufacturers themselves
use the term to mean something specific in a binary system.

 

[DevilsPGD]

In message <[email protected]> "GT"

There is no scientific definition of mega
where it means 1,024,000 - this is wrong. This definition of mega is widely
used (and dare I say accepted) by some in computing.

No, it's not.

There are even websites
that state mega = 1,024,000, or 2 to the power 10, but it is wrong.

If you're trying to discuss one megabyte, 1,024,000 is just wrong either
way, as is 2 to the power of 10.

1,000,000 is correct in normal metric units.

1,048,576 is correct in established binary computation.

2^20 is also correct in established binary computation.

Is it consistent? No. Is that a problem? Sometimes.

Mega is
a scientific, mathematical term meaning 10 to the power 6.

Like billion is a scientific, mathematic term, right?

 

[GT]

... and in the computer industry it is a different value
when referring to a binary value with byte or bit

Like I already wrote, terms can mean different things. Like
I already wrote, even the memory manufacturers themselves
use the term to mean something specific in a binary system.

It doesn't matter what number base you are operating in. A quantity is a
quantity. 10 bits is the same quantity as 10 cars. 1000 houses is the same
quantity as 1000 bytes. 1 kilometre (1000 metres) is the same quantity as 1
kilobyte (1000 bytes).

1,000 = 1 thousand = kilo = 10^3
1,000,000 = 1 million = mega = 10^6
1,048,576 = 1.048576 million = a number derived from raising 2 to the power
20. It happens to be quite close to 1,000,000, but it does not change the
basic mathematics system. A quantity described as 'mega' is 1,000,000 units
(bits, bytes, apples, cars, atoms) and we cannot use any other number in
place of 1,000,000 when talking about 'mega'. To do so would render all
calculations based upon it as unreliable and wrong.

 

[GT]

In message <[email protected]> "GT"

[trimmed]
If you're trying to discuss one megabyte...

1,000,000 is correct in normal metric units.

1,048,576 is correct in established binary computation.

No. That figure is incorrect, but accepted by some in the computer industry.
It doesn't matter what base you are working in. mega is 10^6.

2^20 is also correct in established binary computation.

Nope - not correct, just a number that is misused in the computing field -
nothing to do with binary computation! 2^20 is not even a binary number!
2^20 is a decimal number used by some in the computing field to represent
mega as it conveniently equates to a number close to the actual mega figure.
It is simply an approximation to mega and any calculations or statements
made using it are inherrantly unreliable - as demonstrated below! Please
don't be sucked in by a wikipedia reference!! mega is a term used to
describe quantity and that quantity is 1,000,000. There are no other
meanings of mega.

Is it consistent? No. Is that a problem? Sometimes.

Consistency is not an issue/question - correctness is the problem here
making it a big problem. As established centuries ago and now used in every
walk of life, including some areas of computing mega means 10^6 or
1,000,000.

In datacomms for example, the correct meaning of mega is used and a line
capable of 1 megabit can transfer 1,000,000 bits per second. So 8 megabits
is 8,000,000 bits per second. As there are 8 bits in a byte, 1 megabyte = 8
megabits. So 1 megabyte = 8,000,000 bits or 1,000,000 bytes per second.
Simple, mathematically correct and reliable.

Lets ignore stop and start and parity bits. On this 1 megabyte connection,
the line can transfer 1,000,000 bytes per second. If everyone in the
computing field used the correct meaning of mega, then to fill up 256MB of
RAM, this would take 256 seconds. However in memory terms, 256MB of RAM
isn't taken to mean 256,000,000 bytes. When we in the computing field refer
to 256MB of RAM, we are actually talking about 268.4MB!! So filling the
memory at 1,000,000 bytes per second will actually take 268.43 seconds! An
apparent extra 12.43 seconds came from the incorrect use of MB.

Anyone choosing to use 1,048,576 for mega will find that equations fail to
add up! They will discover that they don't have as much space as they
thought on a hard disk for example!!

There is a term invented for this 1,048,576 figure that everyone keeps
quoting - see the subject of this topic, but it certainly isn't 'mega'!

 

[kony]

It doesn't matter what number base you are operating in. A quantity is a
quantity. 10 bits is the same quantity as 10 cars. 1000 houses is the same
quantity as 1000 bytes. 1 kilometre (1000 metres) is the same quantity as 1
kilobyte (1000 bytes).

Wrong, and even the memory manufacturers themselves agree.

Write to every memory manufacturer and have them follow your
system and then you begin to be right. Until that happens
all the evidence is against you, that giga, mega, etc -byte
or -bit are not purely decimal system values.

How can this be hard to understand? Do you need to take
another look at a memory module's capacity for confirmation?

Different number system, different industry, different
value.

BTW, scientists DO consider gigabyte to mean what the
computer industry long ago defined because the industry
CREATED THE TERM SPECIFICALLY TO MEAN A CERTAIN VALUE.

You don't have to like the how or why, that's just the way
it is.

 

[GT]

Kony, every day in the this group I bow to your knowledge in the hardware
field, but we are just never going to agree on this one!

Wrong, and even the memory manufacturers themselves agree.

Of course they would agree - they invented the misinterpretation!

Write to every memory manufacturer and have them follow your
system and then you begin to be right. Until that happens
all the evidence is against you, that giga, mega, etc -byte
or -bit are not purely decimal system values.

I don't need to write to anyone as it isn't my system. Its called
mathematics and everyone else in the world seems to manage it without
difficultly - its only some in the computing field that have a problem
understanding the terms!

How can this be hard to understand?

Precisely my point: Mega means million, not 1.048576 million!! Not hard to
understand at all, so why can't everyone grasp this!

Do you need to take
another look at a memory module's capacity for confirmation?

Different number system, different industry, different
value.

Its not a different number system - why do you insist on quoting number
systems - this is irrelevant. There is no number system when you are
counting things. We are measuring quantity and happen to be counting it in
decimal (not binary). A quantity is a quantity. Your argument is empty until
you can explain how is 1000 bytes is a larger quantity than 1000 apples? Its
not. 1 kilo is 1 kilo is 1000. End of story.

BTW, scientists DO consider gigabyte to mean what the
computer industry long ago defined because the industry
CREATED THE TERM SPECIFICALLY TO MEAN A CERTAIN VALUE.

You are wrong on a vital point there - the industry didn't *create* the
term!! And I don't know a single scientists who abandons scientific terms
and gets their 'sums' wrong! The term kilo, mega etc were devised centuries
before computing industry existed. Some in the industry incorrectly adjusted
the term and has been misused it ever since. Unfortunately, many people and
companies played along and now it has stuck, yet there are those of us who
refuse to accept the incorrect interpretation of these clearly defined and
well established terms.

You don't have to like the how or why, that's just the way
it is.

Absolutely!

 

[Grinder]

Ok, I officially regret my choice of title for this thread.

 

[kony]

we are just never going to agree on this one!

Ok, then let's not spend any more time on it.

 

[kony]

Ok, I officially regret my choice of title for this thread.

But did Paul's link help? We were kinda wanting to hear if
you had resolved this.

If not, what are the markings on the individual chips on the
memory? IE - I'd assumed you gave the module label markings
already but not the chips themselves... thinking back it was
16 on a double sided module IIRC.

The main thing is, there's not likely anything you can do to
make this module show up as 256MB in that board if it's only
appearing as 128MB now. The CPU-Z report was very strange
as if the detected amount and SPD amount were backwards.

 

[Grinder]

But did Paul's link help? We were kinda wanting to hear if
you had resolved this.

As to the first issue, about what technology is in use, we're at a bit
of a stalemate because of conflicting descriptions on the web, and even
from CPU-Z itself.

As for the second, some general background, I think I've gained some ground.

If not, what are the markings on the individual chips on the
memory? IE - I'd assumed you gave the module label markings
already but not the chips themselves... thinking back it was
16 on a double sided module IIRC.

That's correct, there are 16 chips--eight on each side. The individual
chips are marked as: 48LC16M8A2, which suggests 16Mx8 chips, 16 of them,
for a total of 256MB/MiB.

Searching 48LC16M8A2 at google turns up a number of hits that suggest a
module made from these chips will be 128MB/MiB if it's single-sided, or
256MB/MiB if double-sided.

The main thing is, there's not likely anything you can do to
make this module show up as 256MB in that board if it's only
appearing as 128MB now. The CPU-Z report was very strange
as if the detected amount and SPD amount were backwards.

Assuming all the speculation above is correct, how do I match it up with
my mainboard's vocabulary? ie, Is it 64, 128 or 256 Mbit technology?

 

[Paul]

As to the first issue, about what technology is in use, we're at a bit
of a stalemate because of conflicting descriptions on the web, and even
from CPU-Z itself.

As for the second, some general background, I think I've gained some
ground.


That's correct, there are 16 chips--eight on each side. The individual
chips are marked as: 48LC16M8A2, which suggests 16Mx8 chips, 16 of them,
for a total of 256MB/MiB.

Searching 48LC16M8A2 at google turns up a number of hits that suggest a
module made from these chips will be 128MB/MiB if it's single-sided, or
256MB/MiB if double-sided.


Assuming all the speculation above is correct, how do I match it up with
my mainboard's vocabulary? ie, Is it 64, 128 or 256 Mbit technology?

The 16M8 is a total of 128 megabits. Dividing the number by 8, that is a
16Megabyte memory. It has a x8 interface (so 8 of them are needed to
make a 64 bit wide array, forming one "rank" of memory).

So the question remains as to why the SPD information doesn't seem
to match. When using CPUZ, you select the slot to display from a tiny
menu. Does it still say the stick is only 128MB, when in fact it
physically contains 256MB of chips ?

In years past, before SPD existed, the BIOS determined the memory
size by "probing". We used to do that on some of the proprietary
computers we used to build. If you wrote past the end, during
the BIOS test, then the read back value would fail to verify.

The BIOS today may consult the SPD, for initial setup, but may still use
probing to determine the "end of memory" on each chip select. Otherwise,
for those computers where there is a density mismatch (440BX), how does the
computer actually set up the chip select for half the normal memory
space ? It doesn't seem to rely on the SPD alone. I would consider it
a bit strange though, if it actually searched past the SPD declared
value, because that would imply the SPD was really worthless
Well, at least it still has those timing values written in it.

By the way, the SPD on your stick of RAM is one of those "slightly
bogus" ones. The memory I have in this computer, has real serial
numbers written into the SPD chips. Some manufacturers prepare ROM
chips in advance, and each one of those is identical. They set the
serial number to FFFFFFFF. It is more trouble to use an EEPROM
for the SPD, and spend a few seconds writing a unique set of values
in the stick, but some follow the rules and do it right. The idea
is, it is to the manufacturer's advantage to put a unique number in
it, for easier tracking and verification during a warranty claim.
It would make it easier to identify a counterfeit, if the serial
numbers were unique and recorded at the plant.

Paul

 

[Grinder]

The 16M8 is a total of 128 megabits. Dividing the number by 8, that is a
16Megabyte memory. It has a x8 interface (so 8 of them are needed to
make a 64 bit wide array, forming one "rank" of memory).

So the question remains as to why the SPD information doesn't seem
to match. When using CPUZ, you select the slot to display from a tiny
menu. Does it still say the stick is only 128MB, when in fact it
physically contains 256MB of chips ?

Absolutely.

I installed the module back into the computer that can only see it as
128MB, and ran CPU-Z. The SPD tab was identical, unsurprisingly, the
system tab was a bit different:

1st Machine 2nd Machine
GENERAL FRAME
Type: SDRAM SDRAM
Size: 256 MBytes 128 MBytes
Bank Interleave: none (blank)

TIMINGS FRAME
Frequency: 100.0 MHz 132.9 MHz
FSBRAM: (blank) 3:4
tCL: 3.0 clocks 3.0 clocks
tRCD: 3 clocks 3 clocks
tRP: 3 clocks 3 clocks
tRAS: 6 clocks 6 clocks

 

[Paul]

Absolutely.

I installed the module back into the computer that can only see it as
128MB, and ran CPU-Z. The SPD tab was identical, unsurprisingly, the
system tab was a bit different:

1st Machine 2nd Machine
GENERAL FRAME
Type: SDRAM SDRAM
Size: 256 MBytes 128 MBytes
Bank Interleave: none (blank)

TIMINGS FRAME
Frequency: 100.0 MHz 132.9 MHz
FSBRAM: (blank) 3:4
tCL: 3.0 clocks 3.0 clocks
tRCD: 3 clocks 3 clocks
tRP: 3 clocks 3 clocks
tRAS: 6 clocks 6 clocks

In CPUZ, if you go to "About", there is a Register Dump. It will
dump a file "cpuz.txt". In there, you'll see something like

Dump Module #1
0 1 2 3 4 5 6 7 8 9 A B C D E F
00 80 08 07 0D 0A 02 40 00 04 50 60 00 82 08 00 01
10 0E 04 04 01 02 20 C0 00 00 00 00 28 28 28 28 40
20 70 70 40 40 00 00 00 00 00 37 46 30 28 50 00 00
30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 85 ...

Well, you won't see those particular values, because that is
a dump of my 512MB DDR stick, while yours is SDRAM.

JEDEC has documents to decode those numbers. This doc is
just a guess, as being the one for SDRAM. I used an outside
search engine, rather than messing with the JEDEC search option.
Byte 5 (decimal) and Byte 31 (decimal), as seen on page 20,
define the capacity of each bank. Byte 5 should say 0x02 hex,
meaning there are two banks (double sided). Byte 31 should
read 0x20 hex, to indicate 128MB per bank, for a total of
256MB.

http://www.jedec.org/download/search/4_01_02_05R12.PDF

Have a look at the dump table, and see what your byte 5
and byte 31 show for the module. (Note - the above table
is oriented in hex form, so byte 31 decimal is the second row
right-most byte, as in byte 0x1F, and has a value of 0x40.)

The stuff above 3F, I didn't copy, because it has things like
the serial number and manufacturer ID.

Paul