Recognizing Double-sided DIMMs with x16 organization

memory

How to check if the RAM stick is a Double-sided DIMMs with x16 organization?

I have bought a couple of DIMMs which are not working as expected and since my motherboard states that it doesn't support Double-sided DIMMs with x16 organization so I am trying to find ways to check if I have bought an incompatible RAM stick.

lshw on 64bit Ubuntu identifies my product as NT2GT64U8HD0BY-AD

Its a 2GB PC2 – 6400 CL6 240 Pin DIMM

How can I check if its a Double-sided DIMMs with x16 organization?

Best Answer

It's an old post - but if anyone stumbles on it:

The standard terminology is 1Rx8, 1Rx4, 2Rx8, 1Rx16 etc.

The first number before the R is the RANK of the RAM. The 2nd number (x4, x8, x16) is the number of bit of the data bus of each DRAM chip on your module.

Since any modern RAM has a 64 bit wide data bus, you can now calculate from the number of chips on the memory module which of the x4, x8 or x16 it is:

Assuming with have single-rank memory (1R...), it goes like this:

4 chips = x16 (4 chips x 16bit = 64 bit total)
8 chips = x8  (8 chips x 8 bit = 64 bit)
16 chips = x4 (16 chips x 4 bit = 64 bit)

With dual-rank memory (2R ...) you just have to double this - they typically have chips on both sides. So a total of 8 chips is then x16 etc.

Hope this helps someone.

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