P2B-S Ram Problem

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Mike

Why is it that when I put two 256 mb SDRAM sticks in I don't get 512 I
continue to get 256? This is Kingston KVR133X64C2/256.
256MB 133MHz Non-ECC CL2 DIMM
Standard 32M X 64 Non-ECC 133MHz 168-pin Unbuffered DIMM (SDRAM, 3.3V, CL2,
Gold

What am I missing? Thanks guys this board has always been very helpful,
Mike
 
By the way this is a P2B-S Revision 1.02, I think it has bios version 1.14,
but I am not sure of that and will look if that is an issue, Thanks, Mike

The Kingston site says the board calls for
KVR100X64C3/256
256MB 100MHz Non-ECC CL3 DIMM
Standard 32M X 64 Non-ECC 100MHz 168-pin Unbuffered DIMM (SDRAM, 3.3V, CL3,
Gold

Will CompUSA exchange these lifetime memory modules for the PC100 if that is
my problem?
 
Mike said:
Why is it that when I put two 256 mb SDRAM sticks in I don't get 512 I
continue to get 256? This is Kingston KVR133X64C2/256.
256MB 133MHz Non-ECC CL2 DIMM
Standard 32M X 64 Non-ECC 133MHz 168-pin Unbuffered DIMM (SDRAM,
3.3V, CL2, Gold

What am I missing? Thanks guys this board has always been very
helpful, Mike
Click to expand...

It has to do with the density and organization of the chips on the module.
Read here:

http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html
 
Mike said:
By the way this is a P2B-S Revision 1.02, I think it has bios version 1.14,
but I am not sure of that and will look if that is an issue, Thanks, Mike

The Kingston site says the board calls for
KVR100X64C3/256
256MB 100MHz Non-ECC CL3 DIMM
Standard 32M X 64 Non-ECC 100MHz 168-pin Unbuffered DIMM (SDRAM, 3.3V, CL3,
Gold

Will CompUSA exchange these lifetime memory modules for the PC100 if that is
my problem?
Click to expand...

KVR133X64C2/256 has 8 chips internally organised as 8M x 8-bit x 4 banks:

http://www.valueram.com/datasheets/KVR133X64C2_256.pdf

KVR100X64C3/256 has 16 chips internally organised as 16M x 8-bit x 2 banks:

http://www.valueram.com/datasheets/KVR100X64C3_256.pdf

The 440BX chipset on the P2B-S only supports 2 banks (aka double-sided),
so it only sees half of the 4-bank KVR133X64C2/256 modules you
purchased. The 2-bank KVR100X64C3/256 modules will work at full capacity.

P2B
 
By the way this is a P2B-S Revision 1.02, I think it has bios version 1.14,
but I am not sure of that and will look if that is an issue, Thanks, Mike

The Kingston site says the board calls for
KVR100X64C3/256
256MB 100MHz Non-ECC CL3 DIMM
Standard 32M X 64 Non-ECC 100MHz 168-pin Unbuffered DIMM (SDRAM, 3.3V, CL3,
Gold

Will CompUSA exchange these lifetime memory modules for the PC100 if that is
my problem?
Click to expand...

I've had 4x256MB (running at 100MHz) in my P2B-S 1.03 .
I removed some of it, because it was too much of a good
thing for Win98SE (barfs on 1GB of RAM). This is what I bought:

CT32M64S4D7E    

The Crucial page for the P2B-S is here. I got PC133 CAS2
memory, and run it at 100MHz. (Reason being, at the time,
it was the highest performance, and was the same price
as the slower stuff.)

http://www.crucial.com/store/listpa...oards&mfr=ASUS&tabid=AM&model=P2B-S&submit=Go

The modules are 256MB and have 16 of these chips. The
chips are 16Mx8 (the so-called low density chips). (I read
the part number off a memory chip and searched on the Micron
site, to find this link.)

http://www.micron.com/products/dram/sdram/part.aspx?part=MT48LC16M8A2TG-7E

I have a few datasheets for Kingston, on disk (I may have
downloaded these while shopping for RAM).

KVR133X64C3Q/256 = 16 chips of 16Mx8 size
KVR133X64C3/256 = 8 chips of 32Mx8 size
KVR133X64C2/256 = 8 chips of 32Mx8 size <-- You bought high density

You can make up your own URL for the datasheets, following the format
in this example. There is a web page that lists many of these
sheets, but I'm lazy, and just editing the URL is easier.

http://www.valueram.com/datasheets/KVR133X64C2_256.pdf

Now, the Kingston page for the P2B-S is only listing PC100
DIMMs, and chances are, they are constructed with the 16Mx8
chips, and not the 32Mx8 you bought. There is a difference
between KVR133... and KVR100. The difference is not
only speed, it is also the size and number of chips. As
illustrated by the three examples above, each module
can have a different construction (which sucks as a
decision on Kingston's part).

This is the Kingston page for P2B-S. I downloaded the two
DIMMs most relevant to what you want to do, and both of
them use 16Mx8 chips. The problem, then, is you bought
133Mhz DIMMs that happen to use 32Mx8 chips and are not
on the recommended list because of that. And the ones
with the "Q" on the end, might not be available any
more (ask your vendor if they are still listed).
I think that is possibly why I bought the Crucial,
because I could get 16Mx8 chips, PC133, CAS2, in one
nice package.

KVR100X64C2/128 128MB 100MHz Non-ECC CL2 DIMM
KVR100X64C2/256 256MB 100MHz Non-ECC CL2 DIMM <--- 16 chips of 16Mx8 size
KVR100X64C3/64 64MB 100MHz Non-ECC CL3 DIMM
KVR100X64C3/128 128MB 100MHz Non-ECC CL3 DIMM
KVR100X64C3/256 256MB 100MHz Non-ECC CL3 DIMM <--- 16 chips of 16Mx8 size
KVR100X72C2/256 256MB 100MHz ECC CL2 DIMM
KVR100X72C3/128 128MB 100MHz ECC CL3 DIMM
KVR100X72C3/256 256MB 100MHz ECC CL3 DIMM

So, the KVR133X64C3Q/256 should work, and would be a CAS3
part. The KVR100X64C2/256 and KVR100X64C3/256 are PC100
and should work from a density perspective. I don't know
what clock rate you are planning on using, so pick either
a PC133 or PC100 choice as appropriate to your clock rate.

Roland is the guy who figured this stuff out, long ago.

http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html

Paul
 
P2B said:
KVR133X64C2/256 has 8 chips internally organised as 8M x 8-bit x 4 banks:

http://www.valueram.com/datasheets/KVR133X64C2_256.pdf

KVR100X64C3/256 has 16 chips internally organised as 16M x 8-bit x 2 banks:

http://www.valueram.com/datasheets/KVR100X64C3_256.pdf

The 440BX chipset on the P2B-S only supports 2 banks (aka double-sided),
so it only sees half of the 4-bank KVR133X64C2/256 modules you
purchased. The 2-bank KVR100X64C3/256 modules will work at full capacity.

P2B
Click to expand...

There are "ranks" and there are "banks". A double sided DIMM is
two "ranks". The structure inside each chip is the "banks".
(At least I've seen "ranks" used to break the naming convention
problem of both levels using the term "banks".)

From the 440BX datasheet, it says:

DRAM type: Extended Data Out (EDO) (mobile only) or Synchronous
(SDRAM) DRAM controller optimized for dual/quad-bank SDRAM
organization on a row by row basis

Further in the datasheet, there is a reference to quad bank
(inside-the-chip banks) addressing as well. BA[1:0] would
address four internal chip banks:

MAA/B[12:11] function as Bank Addresses
(BA[1:0], or Bank Selects).

I thought the deal with 32Mx8 versus 16Mx8, was one of addressing
bits. I think the chip has 12 true address bits, and the two bits
functioning as BA[1:0]. A 32Mx8 chip can have an orientation of
13 x 10 (plus the two bank bits), which is one too many to be
addressed by a 12 address Northbridge. I could be mistaken.

Rows, columns, banks, ranks. I think the problem needs more
dimensions :-)

Paul
 
Paul said:
that is
KVR133X64C2/256 has 8 chips internally organised as 8M x 8-bit x 4 banks:

http://www.valueram.com/datasheets/KVR133X64C2_256.pdf

KVR100X64C3/256 has 16 chips internally organised as 16M x 8-bit x 2 banks:

http://www.valueram.com/datasheets/KVR100X64C3_256.pdf

The 440BX chipset on the P2B-S only supports 2 banks (aka double-sided),
so it only sees half of the 4-bank KVR133X64C2/256 modules you
purchased. The 2-bank KVR100X64C3/256 modules will work at full capacity.

P2B
Click to expand...


There are "ranks" and there are "banks". A double sided DIMM is
two "ranks". The structure inside each chip is the "banks".
(At least I've seen "ranks" used to break the naming convention
problem of both levels using the term "banks".)

From the 440BX datasheet, it says:

DRAM type: Extended Data Out (EDO) (mobile only) or Synchronous
(SDRAM) DRAM controller optimized for dual/quad-bank SDRAM
organization on a row by row basis

Further in the datasheet, there is a reference to quad bank
(inside-the-chip banks) addressing as well. BA[1:0] would
address four internal chip banks:

MAA/B[12:11] function as Bank Addresses
(BA[1:0], or Bank Selects).

I thought the deal with 32Mx8 versus 16Mx8, was one of addressing
bits. I think the chip has 12 true address bits, and the two bits
functioning as BA[1:0]. A 32Mx8 chip can have an orientation of
13 x 10 (plus the two bank bits), which is one too many to be
addressed by a 12 address Northbridge. I could be mistaken.

Rows, columns, banks, ranks. I think the problem needs more
dimensions :-)

Paul
Click to expand...

Yeah, like I need to aggravate the headache I get thinking about it :-)

I now buy my 256MB 440BX RAM modules used. They have to have 16 chips
and be offered on a try-before-buy basis.

I gave up on using part number alone after buying a CT32M64S4D7E, with
Micron 16M8 chips on it, that only works as 128MB - it must be partially
defective as I have several identical modules that work as 256MB, but
that was the last straw for me :-(

P2B
 
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