Getting lucky mixing DDR modules?

[Retrorockit]

Re: Getting lucky mixing DDR modules?

I'm not saying ranks didn't exist. I'm saying it's a different issue. Ranks have to do with the arrangement of the data.
Density is a physical feature of the memory chip itself. Older Intel computers require older x64 memory chips. AMD and newer Intel computers can run either x128, or x64.
Sometimes this makes a huge difference in price and availability of some modules.
AMD stuck with DDR2 longer than Intel and accessed newer memory chip technology that Intel computers couldn't run. This carried on into earlier DDR3 computers.
This is the issue with AMD only RAM (X128 density), and Dell compatible RAM (x64 density) modules for older computers.
This is listed on Crucial memory modules and can help you get it right the first time on older Intel and especially Dell computers. I think Dell just refused to update their BIOS to run newer modules.

On this page there is a chart showing different density, and ranks on old DDR Server RAM 1GB modules. The chart wouldn't copy intact to this post so just the link.
https://en.wikipedia.org/wiki/DDR_SDRAM

[eccerr0r]

Re: Getting lucky mixing DDR modules?

Still not explaining x128 chips on DIMMs other than saying "requiring" but down to a bit level detail... Why?

Examples do not explain Why and they don't even give a x128 example.

As piernov said,

In theory you could have a single "x128" chip on the board combining 2 channels but that sounds kinda crazy.

This implies no sockets, and soldered onto the board which I agree would work but kind of unusual as it means these chips cannot be used on modules which split up at 64-bit boundaries...
... But you claim that you can put this actually can be on ONE 64-bit module for in a dual-channel motherboard, which is even MORE crazy. So explain this... down to a bit level detail, not explaining it away "just because it works for certain [AMD] MCs." Schematics please!

[piernov]

Re: Getting lucky mixing DDR modules?

Ranks are exactly as I described, the link you provided confirms it with a different wording. It is indeed different from the organization of the chip, but it is related due to the constraint of having a fixed 64 bits memory bus.
On the other hand 64 bits and 128 bits data bus width in single channel and dual channel respectively is an entirely different matter. Both Intel and AMD have supported dual channel for a long time, since the i865 for Intel and socket 939 for AMD (but some northbridges for K7 did support dual channel already).
I'm still not sure what your x64 and x128 refer to.

Looking harder on Google I could find a few references to x128 LPDDR3 chips that may have existed from Micron but are now marked as obsolete: https://www.micron.com/products/dram...pddr3-obsolete
This is of course an extremely rare occurrence and I've personally never seen these chips used anyway. (finding x64 chips actually used somewhere is already very difficult)

Also I described where exactly the compatibility issue with "AMD-only" DDR lies (both in this thread and the other that was dedicated to this question). It is the additional column address bit required by x4 chips that is not supported by some Intel memory controllers.

All of this depends on the memory controller and the routing of the memory bus on the board. It does not depend on the BIOS or the manufacturer. But of course there are other limitations and incompatibility caused by BIOS, that may not allow using some RAM sticks. (BIOSes are often buggy, nothing surprising there)

Additionally, to clarify the use of "density": it is typically used by RAM chips manufacturer for the total size of a single chip. There are some implications on the memory organization, but you can have various memory organizations for the same density. This is perfectly illustrated by the link I posted just above.

[eccerr0r]

Re: Getting lucky mixing DDR modules?

I'm still not sure what your x64 and x128 refer to.

See now piernov is also wondering about these so-called x128's...

Retrorockit, again, care to explain at a bit level, not "It works with AMD"?

[Retrorockit]

Re: Getting lucky mixing DDR modules?

This is from an item listed for sale. I believe this applies to all DDR2 era, and LGA775 DDR3 OEM computers. Some of the aftermarket MB can run these I've been told. I think that Intel started to accept high density RAM when they moved the memory controller onto the CPU ( but I haven't tested this). I think I've given a correct and useful answer to the OPs question. In 2GB DDR2 modules this usually shows up as high density 8 chips on one side, and low density 16 chips, 8 on each side. I hope this answers your "so called" question.
I'm sure this vendor would have loved to sell these to Intel users if he could.


"All high density 1GB modules are made with 16 chips (8 chips on each side) using 128MX4 device.

All low density 1GB modules are made with 16 chips (8 chips on each side) using 64MX8 device.

The item is high density and it can not work in any intel cpu motherboard.It only support AMD chipset motherboard.
Not work with All DELL,IBM,Apple,HP,Compaq,Gateway,Acer.Lenovo,Emachines,Packbell Computers."

[eccerr0r]

Re: Getting lucky mixing DDR modules?

So you gave misleading and incorrect answers. Now to finally get the correct declarations out there:

- 128M is not the same as x128.
- 128M does not declare density.
- 128Mbit is a density, but 128Mx4 devices are not 128Mbit devices. They are 512Mbit devices.
- 64Mx8 devices are ALSO 512Mbit devices. They are the exact same density as 128Mx4 devices.
- Number of chips on a side has no implications on its organization
- No matter what, you still need 64 bits, no less, no more, to fill a row on a memory module
- SOME CHIPSETS have limits on what organizations are acceptable for use due to address line limits, refresh limits, etc.

So, people need to stop saying "high density" "low density" and "x128" like marketing "experts" because these are misnomers, inconclusive, and WRONG.

[Retrorockit]

Re: Getting lucky mixing DDR modules?

So you gave misleading and incorrect answers. Now to finally get the correct declarations out there:

- 128M is not the same as x128.
- 128M does not declare density.
- 128Mbit is a density, but 128Mx4 devices are not 128Mbit devices. They are 512Mbit devices.
- 64Mx8 devices are ALSO 512Mbit devices. They are the exact same density as 128Mx4 devices.
- Number of chips on a side has no implications on its organization
- No matter what, you still need 64 bits, no less, no more, to fill a row on a memory module
- SOME CHIPSETS have limits on what organizations are acceptable for use due to address line limits, refresh limits, etc.

So, people need to stop saying "high density" "low density" and "x128" like marketing "experts" because these are misnomers, inconclusive, and WRONG.

Those are the terms the manufacturers, and vendors are using. I didn't invent any of them. If you are shopping for memory for an old Intel computer and you don't want to have compatibility issues this is what you need to be looking at. AMD, high density, and x128 are not marketing terminology. They are the terms used to describe RAM that won't run in many Intel computers.
The fact that you don't understand something doesn't make it "wrong".

[Retrorockit]

Re: Getting lucky mixing DDR modules?

At the chip level 64M or 128M is the term used.
When assembled into modules it becomes x128 or x64 to show the size of the module. 512x64 is the same size module as 256x128. Both would be 4GB modules regardless of the number of chips used, or how many Ranks they're wired to produce.

" SOME CHIPSETS have limits on what organizations are acceptable for use due to address line limits, refresh limits, etc."
That is exactly what I've been saying. Intel chipsets don't support the x128, or 128M organiztion of the memory chips.

[eccerr0r]

Re: Getting lucky mixing DDR modules?

Manufacturers do not use improper terminology. Uninformed vendors use "Marketing" terms. What I didn't understand was the improper terminology you used. Now deducing and using the correct terminology, it makes perfect sense.

Improper terminology is at the root, wrong. Two chips that the same number of bits have the same density. There's no technical details shown when a chip is denoted "AMD" or "Intel", and it has no value whether it will work with other memory controllers that are neither AMD nor Intel. And "x128" is completely misleading, which is simply wrong.

I hope you now stand corrected and stop using BS "marketing" terms that gaslight the technical details - if you don't know, you don't know. Don't pretend you know and then use "marketing" to explain it.

[Retrorockit]

Re: Getting lucky mixing DDR modules?

The x64 or x128 spec. can be hard to find. Crucial RAM it's the first digits in the part number.
The terms High Density ,and AMD RAM refer to the same thing= 128M chips.
This makes them useful terminology.

[brethin]

Re: Getting lucky mixing DDR modules?

Covid has too many people dickheads, everyone here knew and that had a clue what Rettro was referring too yet some want to hit pick terms and be dickheads, very sad. Memory 101 low density and high density, get over it if he call it 64 and 128 already.

[brethin]

Re: Getting lucky mixing DDR modules?

It's just old memory for gods sacks it's not bitcoin or something worth anything.��

[eccerr0r]

Re: Getting lucky mixing DDR modules?

You can have your 4096 bit x1 memory. It's really high density. Just pass by that 64Mx8 low density chip.

[brethin]

Re: Getting lucky mixing DDR modules?

Low density is compatible with everything, high density isn't.

[piernov]

Re: Getting lucky mixing DDR modules?

Next time before insulting people for no reason I'd recommend you to actually read the posts and try to understand what's in them, maybe you can learn something from it. If that's not what you're here for then there are a lot of other places on the Internet better suited for you.

[eccerr0r]

Re: Getting lucky mixing DDR modules?

However the claim was incorrect, even you indicated something was wrong. I don't think there was any undeserved replies here, I'm tired of reading "fake news" that were just parroting what vendors were saying and not truly understanding the electrical details of how things are hooked up.

So it's mostly just one person in this thread that needed to learn the real deal, not me. And I think that's what happened when they did the research and found out they were wrong but tried to disguise it.

[brethin]

Re: Getting lucky mixing DDR modules?

Low density is compatible with everything, high density isn't, it's what a 12 year old computer kid understands, if he is calling it 64 an 128 that's just a bad translation, anyone with 3 brain cells knows what he means and those trying to make drama from it need to get a life and find something else to post about. this thread is dead was solved long ago get over it already.

[eccerr0r]

Re: Getting lucky mixing DDR modules?

It's got to be this way because we say so, don't worry about the man behind the curtains, your brain won't understand anyway...