Question Micron DDR chips of same capacity with different die configurations ?

[antony67543]

Hi
I have a doubt. I have 2 different DDR chips from Micron Technology, both are 4GB capacity with dual channel. But each of them have different die configurations. One has 2 die and the other one has 4 die. Which one should I select? What is the role of the die here?

 

[Aeacus]

I have 2 different DDR chips from Micron Technology, both are 4GB capacity with dual channel.

That's impossible. DDR (aka DDR1) max capacity DIMM is 1GB. So, how you can have 4GB DDR DIMMs?

What is the role of the die here?

Diff would be response time (latency) and heat dissipation.

4GB DDR2 (or DDR3 or DDR4) with 2x dies on DIMM = 2GB per die.
4GB DDR2 (or DDR3 or DDR4) with 4x dies on DIMM = 1GB per die.

Technically, with more dies, heat production is spread out more evenly and RAM response time would be less. But it is actually negligible diff.

Which one should I select?

What matters more, are timings and transfer rate. So, do both RAM sets have the same, identical transfer rate and timings as well? If so, then doesn't matter actually which you pick. If you can't decide, pick by aesthetics.

But when transfer rate and/or timings are different between two sets, then it matters by performance and that, can be noticeable.

 

[antony67543]

That's impossible. DDR (aka DDR1) max capacity DIMM is 1GB. So, how you can have 4GB DDR DIMMs?


Diff would be response time (latency) and heat dissipation.

4GB DDR2 (or DDR3 or DDR4) with 2x dies on DIMM = 2GB per die.
4GB DDR2 (or DDR3 or DDR4) with 4x dies on DIMM = 1GB per die.

Technically, with more dies, heat production is spread out more evenly and RAM response time would be less. But it is actually negligible diff.


What matters more, are timings and transfer rate. So, do both RAM sets have the same, identical transfer rate and timings as well? If so, then doesn't matter actually which you pick. If you can't decide, pick by aesthetics.

But when transfer rate and/or timings are different between two sets, then it matters by performance and that, can be noticeable.

Hi
Actually I didn't exactly mean DDR.
I am using MT62F1G32D4DS -031 WT:B lpddr from micron technology in one of my projects.
That part became obsolete. For that I am looking for alternate and found MT62F1G32D2DS-26 WT:C chip.
The difference between them is the die count. But I dont know the exact reason for the different die configurations of chip with same memory capacity. So that only I asked.
Thanks for your response.

 

[antony67543]

I also have another one doubt.
The part which became obsolete have cycle time 313ps. And the alternate which I found have 218ps. Do I need to do any firmware change here or automatically the cycle time will be sensed and data handling will happen accordingly?

 

[Aeacus]

I am using MT62F1G32D4DS -031 WT:B lpddr from micron technology in one of my projects.

You sure you got the part number right?
Since i looked it up from Google and sole answer i got, is DDR5 32GB single DIMM, and not 2x 4GB as you say it is.
Source: https://www.mouser.com/ProductDetail/Micron/MT62F1G32D4DS-031-RS-WTB-TR?qs=amGC7iS6iy%2BOXbQrHRc4pw==

Same with 2nd one;

MT62F1G32D2DS-26 WT:C

This one is also 32GB single DDR5 DIMM and not a set.
Source: https://eu.mouser.com/ProductDetail/Micron/MT62F1G32D2DS-026-WTC?qs=vvQtp7zwQdP3CetDQetK2A==

The part which became obsolete have cycle time 313ps. And the alternate which I found have 218ps.

Well, this means that the new RAM has tighter timings and if the transfer rate is same between the two, the newer RAM has lower latency (which is better).

Do I need to do any firmware change here or automatically the cycle time will be sensed and data handling will happen accordingly?

Depends on what system you actually have, where you need to use LPDDR and not regular DDR. Laptop? Tablet? Since LPDDR is for those. Desktop and server builds do fine with regular DDR.

But overall, replacing RAM is plug-and-play. Meaning that you shouldn't do anything extraordinary to make the new RAM work.
That is: IF the RAM transfer speed is JEDEC speed and not using XMP/EXPO profile. Or when MoBo/CPU doesn't have other limitations in place for using specific RAM. Also, things are different if we are talking about DDR2, DDR3 or DDR4 (since there are no 4GB DIMMs for DDR1 and DDR5).

 

[antony67543]

You sure you got the part number right?
Since i looked it up from Google and sole answer i got, is DDR5 32GB single DIMM, and not 2x 4GB as you say it is.
Source: https://www.mouser.com/ProductDetail/Micron/MT62F1G32D4DS-031-RS-WTB-TR?qs=amGC7iS6iy%2BOXbQrHRc4pw==

Same with 2nd one;

This one is also 32GB single DDR5 DIMM and not a set.
Source: https://eu.mouser.com/ProductDetail/Micron/MT62F1G32D2DS-026-WTC?qs=vvQtp7zwQdP3CetDQetK2A==


Well, this means that the new RAM has tighter timings and if the transfer rate is same between the two, the newer RAM has lower latency (which is better).


Depends on what system you actually have, where you need to use LPDDR and not regular DDR. Laptop? Tablet? Since LPDDR is for those. Desktop and server builds do fine with regular DDR.

But overall, replacing RAM is plug-and-play. Meaning that you shouldn't do anything extraordinary to make the new RAM work.
That is: IF the RAM transfer speed is JEDEC speed and not using XMP/EXPO profile. Or when MoBo/CPU doesn't have other limitations in place for using specific RAM. Also, things are different if we are talking about DDR2, DDR3 or DDR4 (since there are no 4GB DIMMs for DDR1 and DDR5).

Hi
It is not 32GB(GigaByte).
It is 32Gb(Gigabit)=4GB(GigaByte).
And also it is not DDR5. It is LPDDR5. I am using it in my embedded project and not in desktop applications.
Thanks for your reply.

 

[Aeacus]

It is not 32GB(GigaByte).
It is 32Gb(Gigabit)=4GB(GigaByte).
And also it is not DDR5. It is LPDDR5. I am using it in my embedded project and not in desktop applications.

Gave it more in-depth look and yes, it's 32Gb and not 32GB. Also, the RAM is SMD and not regular DIMM. So, that explains why it is 4GB total and LPDDR5.
(For regular DIMMs, there are no 4GB DIMMs of LPDDR5 or DDR5.)

As for compatibility, it depends if the logic board can accept slightly different RAM, once you've used SMT to place the RAM chips onto PCB and soldered the connections.