Here's what 32x4 and 32x64 means!! ( now with diagram)

[DesignDawg]

Hey all,

I've seen a lot of people asking lately what the 32x4 means on the new athlon-only RAM, and what does it mean when it says 32Mx64, and what is the 32Mx4 RAM the same RAM as the 32Mx64? Well, I did some reading, and figured it out.

32M means 32 MegaBITS. Not megabytes. The 32x4 descriotion is the description for each CHIP on the stick of RAM. So, each chip is 32Mx4 which equals 128 Megabits. Right? And 128 megabits time 16 chips on the stickl of RAM equals 2048 Mb of memory, which, when divided by 8 (1 megaBYTE equals 8 megaBITS), gives you the magical cna wonderful number of 256 megabytes! Right? So, that's what the 32x4 means. The 32x64 means the same thing, but it is just odered differently. Basically, the 32M still means 32 megabits, but the 64 simply refers to the 16 chips times 4 (consider the 4 kinda like a multiplier on a processor.) That "multiplier" can be multiplied times the size of the RAM chip or by the number of chips on the PCB. Thus, 32M times 64 once again equals 2048 Mb of RAM, which, divided by 8 gives us 256 MB of RAM. Makes perfect sense, right? Glad I know, because it has been bothering me.

And, apparently, the reason the older chipsets can't read the new 32Mx4 RAM is simply because they can calculate that much memory per chip (32M) In order for them to see it, it has to be 16x8 or some other equivalent.

This is, of course, in layman's terms. I know the 4 isn't really a "multiplier", but it's a good simple explanation. Better than saying "It just means it's higher density"

[EDIT: The diagram is lower down, in my last post.]


Ricky
DesignDawg

 

[goophie]

so bouth 32x4 and 32x64 has 16 chips on the stick? or does the 32x64 have 4 chips on the board and 32x64 Mb on each chip?

And isn't it that newer motherboards can't read the 32x64? or am i wrong here?

 

[edblor]

TY Ricky!!!!

Edblor

That helps and explains a lot!!

 

[DesignDawg]

goophie,

The 32x64 and the 32x4 are the same thing. There are 16 chips of 32x4. The cheap cheap sticks of 256 MB right now ($70.00) are called 32x4 and 32x64. It's the EXACT SAME RAM. So, you're SORTA wrong, yes. Newer motherboards can definitely read 32x64. I have two with 32x64 in them right now.

ALSO....I forgot to mention this: Even though I say 32x64 and 32x4 are the same thing, I NEED TO BE CLEAR that 16x8 and 32x64 are the same thing as well. I know that's confusing. Let's just say that all 32x4 256 MB RAM is 32x64, but NOT ALL 32x64 is 32x4. Is that confusing? THE PROBLEM is with the size of the memory modules in each chip. Older boards can see more of smaller pieces of memory, but can't see the bigger pieces. That's why it can see 8 pieces of 16 per chip, but not 4 pieces of 32 per chip. Understand?

Ricky
DesignDawg

 

[DesignDawg]

To be a little more specific about what I call a "multiplier", the multipoier is actually referred to as the SDRAM width, and is measured in terms of X[number]. That's where the X4 and X8 comes from. Basically, it's kinda like layers. Think of each chip of RAM as a stack of smaller chips of RAM. a 32x4 chip is a chip with a SDRAM width of x4 and (1 bank X 4 banks on SDRAM) on each of these "layers" or banks, is a memory module 256 bytes in size, which is 32 MB. So, if you take those 4 banks of 32 MB and "stack" them to make one "chip" of SDRAM (the actual things that look like chips on your stick of RAM, we have a 32Mx4 chip. if you have 16 of them, you get 256 MB of RAM. The thing is, what we call a "chip" is just a group of smaller "chips." --So like I said, you don't actually have 16 "chips" of 32Mb of RAM. You ACTUALLY have 16x4 "chips" of 32 Mb of RAM. They just happen to be groupd in 4's.
On the older chipsets, they simply can't read all 32M from one "layer" or bank, so the same amount of memory has to be broken up into smaller "layers" and more of them. SO, you still have 32Mx64, but it's just broken down so that each "chip" of RAM on your stick of RAM has 8 "layers" instead of 4, and they are half as big. Make sense? I hope I have shed some light on this for someone.

I'll make a diagram (in simple terms) and post it in a few minutes so you'll be able to SEE what I'm saying.

Ricky
DesignDawg

 

[edblor]

I'm not confused little doggie!!

And I dig your sig bud!!

Edblor

 

[DesignDawg]

OK....

Here's the diagram

Like I said, it's very simplified, so all you SDRAM DESIGNERS out there, know that I'm not professing to know every aspect of how SDRAM works. I just read enough Whitesheets that I think I can satisfactorily explain what all these terms mean that have been floating around lately.

NOTE: The diagram is one BIG-ASS JPEG. I thought it would be easier than making a web-page. Also, it's not that pretty, but it doesn't need to be. I'm not designing a manual or anything. Hope this answers some questions.

Ricky
DesignDawg

 

[Nih]

thx, I though the picture was pretty good dawg.