What does the x16 stand for in a DDR DIMM?

[Diabolical88]

I'm trying to help my Dad upgrade the memory in his Asus P4PE motherboard as well a troubleshoot some weird problems (possibly related to memory he recently installed). His manual says that the motherboard does not support "x16" memory. I not sure what the "x16" actually refers too.

I know that if for example you have a DIMM that is 64x16 then the total amount of the memory is (64x16)/8 = 128 MB. But what does that x16 stand for, data width? And how do I make sure the memory we buy isn't "x16". Some places don't show the spec.

He wants to add 512MB DDR 2700. Is it possible that a 512 MB chip would even come in a 256x16?

 

[zephyrprime]

It's depth I believe. I might actually correspond to the physical number of bits in a particular direction on the physical chip.

 

[JBT]

I think it actually has to do with the number of actual chips on the Ram IE x16 would be doublesided while x8 would be single sided. Not sure though.

 

[odog]

i believe the x16 is refering to the amount of chips on the dimm.

 

[jjyiz28]

The second factor to consider is the organisation of the RAM cells inside each chip. There are a number of configurations available for the organisation of a single chip. Take the 128Mbit chip as an example. It can be organised as 8mbit x 16 cells, 16mbit x 8 cells, or 32mbit x 4 cells. The last configuration is classed as high density.

Much of the very cheap RAM that you see today is in the form of the final organisation (?? x 4). No Intel chipset is compatible with this RAM, regardless of the overall Mbit size of the RAM chip. VIA Apollo and K?133/266 chipsets ARE compatible with this type of RAM

from anandtech faq..

 

[Diabolical88]

Good info, thanks.

I also did some more research and found some good info on Kingston's site at:

http://www.kingston.com/tools/umg/umg04.asp

About halfway down the page they show a breakdown of what everything actually means.
The "x16" being the width of the chip in bits.