MB says no 128 MB chips or double-sided x16 modules

Just bought a ASUS P5ND2-SLI. The manual specifically says no 128 MB chips or double sided x 16 memory modules. I can't find an explanation for the terminology anywhere. I know what double-sided is, but what is the "x 16".

Also, every site I go to for memory suggestions recommends modules described as 128x64. Does this mean it is a 128 MB chip? Even the QVL at ASUS includes chips described as 128x64.

How can I tell from the specification for the memory modules if they are composed of 128MB chips or are double-sidedX16 modules.

MB accepts up to 2GB DDR2-667 modules. I plan on installing 4 GB running dual channel. Corsair recommends CM2x1024-5400C using 32M x 8 DDR2 SDRAMS.

Thanks for your help.

x16, said, "by sixteen," is part of the IC's construction and details part of how it functions.

The 32x8 you've listed are, "by eight." Basically, the board is saying that it won't support that particular type of IC. HOWEVER, a x16 IC can actually be used and the system fooled into thinking it's something else through certain tweaks of the memory module, regardless that's not the point.

It's pretty rare to find desktop memory modules with x16 IC's, so I wouldn't worry about it anyways, to be honest.

I'm not entirely sure what it's talking about not supporting 128MB chips, this would either be an IC or a whole module, but I'll have to read up on it to be sure!

PLUR

CK

Just bought a ASUS P5ND2-SLI. The manual specifically says no 128 MB chips or double sided x 16 memory modules. I can't find an explanation for the terminology anywhere. I know what double-sided is, but what is the "x 16".

The "x16" refers to the number of chips per rank (side). Thus, a double-rank (double-sided) "x16" module has 16 chips per side (32 chips total).

As for "no 128MB chips", this means you cannot use any modules containing 128MB per chip (which means a density of 1 Gbit). In practical terms, this means that a single-rank (single-sided) 1GB module with only eight chips cannot be used with your mobo, nor can any 2GB or larger module be used. This will limit your motherboard to 4GB total maximum memory, with a maximum of 1GB per memory slot - and all 1GB modules to be used on your mobo must either be double-rank (double-sided) or be single-rank with 16 chips (the latter much less common than the former).

For that reason, most 1GB modules are of the 64M x 8 variety, and thus will work on your mobo. (You may see the 1GB modules being described as "128x64" -- but each IC chip really contains only 64MB on those modules because those modules are double-sided.)

I found a slightly out-of-date primer on XXXXXXXXX's website. According to their site the d x w chip description refers to chip depth (in millions of locations) x chip width in bits, thus the Corsair 32x8 = 256 Mbit chip density.

So far that is understandable.

The "x16" refers to the number of chips per rank (side). Thus, a double-rank (double-sided) "x16" module has 16 chips per side (32 chips total).

RJLeong65, thanks for responding. I'd like to independently verify what you're telling me. Please don't take offense. How do you know the x16 means only one side and not the total for both sides? Is it industry standard terminology to refer to one side or is that wording simply the result of a flawed translation?

The manual specifically says no 128 MB chips

My mistake. This should read 128Mb chips. Is this the total capacity (i.e. 16Mbx8=128Mb) or does this refer to the chip depth (i.e. 128Mbx8=1024Mb)?

XXXX 64x8 DDR2 FBGA Chips on a 1GB module. 64x8=512Mb divided by 8 = 64MB per chip. This would mean 64MB x 16 chips would be required to equal 1 GB. How do I know if they put all on one side or two?

In practical terms, this means that a single-rank (single-sided) 1GB module with only eight chips cannot be used with your mobo, nor can any 2GB or larger module be used. This will limit your motherboard to 4GB total maximum memory, with a maximum of 1GB per memory slot - and all 1GB modules to be used on your mobo must either be double-rank (double-sided) or be single-rank with 16 chips (the latter much less common than the former).

ASUS claims the MB will support up to 16GB memory w/ 64 bit OS and 8GB with 32 bit, but the largest module supported is 2GB. There are only four slots so I don't know one can get 16MB from four 2GB modules. Anyway, doesn't this contradict what you said in the above quote?

Thanks for your input.

CandyKid,

Perhaps you can add to what you offered and help clarify my understanding of chip and modules based on my last post.

Thanks much...

RJLeong65, thanks for responding. I'd like to independently verify what you're telling me. Please don't take offense. How do you know the x16 means only one side and not the total for both sides? Is it industry standard terminology to refer to one side or is that wording simply the result of a flawed translation?

It's just industry standard terminology to refer to one side.

My mistake. This should read 128Mb chips. Is this the total capacity (i.e. 16Mbx8=128Mb) or does this refer to the chip depth (i.e. 128Mbx8=1024Mb)?

128Mb (or 128Mbit) chips are very low density chips. If you refer to 128Mbit chips, then this will apply to double-sided 256MB or smaller modules, or single-sided 128MB or smaller modules. (In other words, 256MB sticks must be single-sided in order to work with that mobo - and 256MB is the smallest-capacity stick that the P5ND2-SLI mobo will support. Thus, the P5ND2-SLI requires memory modules made up of 256Mbit to 1Gbit chips.)

XXXX 64x8 DDR2 FBGA Chips on a 1GB module. 64x8=512Mb divided by 8 = 64MB per chip. This would mean 64MB x 16 chips would be required to equal 1 GB. How do I know if they put all on one side or two?

Refer to the "industry standard" terminology. 64x8 refers to per rank. Thus, a 64x8 1GB module is double-sided.

The memory guide recommends, among others:

Part # : VS1GBKIT667D2

Type : DDR2-667 (PC2-5300)

Size : 1GB Kit (2 x 512MB)

The 2 GB kit for the same 667 is not listed. Does this mean it isn't compatible, something to do with the larger size modules perhaps?

Also, this computer will be used for digital music multi-track recording, photo editing, and video editing. Is there any benefit significant enough to justify the cost of using matched dual-channel pairs? (i.e. XMS2) I'm not a gamer and I only do video occasionally.

Thanks for all the input.:laughing:

The "x16" refers to the number of chips per rank (side). Thus, a double-rank (double-sided) "x16" module has 16 chips per side (32 chips total).

 

As for "no 128MB chips", this means you cannot use any modules containing 128MB per chip (which means a density of 1 Gbit). In practical terms, this means that a single-rank (single-sided) 1GB module with only eight chips cannot be used with your mobo, nor can any 2GB or larger module be used. This will limit your motherboard to 4GB total maximum memory, with a maximum of 1GB per memory slot - and all 1GB modules to be used on your mobo must either be double-rank (double-sided) or be single-rank with 16 chips (the latter much less common than the former).

 

For that reason, most 1GB modules are of the 64M x 8 variety, and thus will work on your mobo. (You may see the 1GB modules being described as "128x64" -- but each IC chip really contains only 64MB on those modules because those modules are double-sided.)

I was partially wrong here, in this case. (Though I was correct about the 128Mbit part.)

The "x16", in this case, refers to memory modules with only four IC chips per side (rank). I stand corrected in this case. "x16" really refers to 16-bit IC's. The restriction limits any compatible memory modules with x16 IC's to single-sided (single-rank) sticks.

In other words, modern Intel and AMD systems technically can use 128MB modules - but they must be of the single-sided x16 configuration; otherwise, the IC density will drop to 128Mbit or lower (which is outside the JEDEC DDR400 specs). By the same token, all compatible 256MB sticks must be single-sided, as well, since double-sided 256MB sticks would require an x16 configuration or 128Mbit IC's.