[SOLVED] Does this SSD have DRAM ? all information are given below

[PhantomXT]

Does this SSD have DRAM ? all information are given below,

PS3111-S11
https://s1p.manualzz.com/store/data/048935537.pdf?k=AwAAAXm9AB0IAAACWGd4psDcdEE4h1NIamR4BkLW66s1

 

[lvt]

Can you post a photo of the back?

 

[popatim]

There's 32mb built into the S11 controller which does not support an external dram module that I am aware of.
This is considered Dram-less as the 32mb does not offer much benefit.

 

[lvt]

Normall, on a card with 256GB like this, you have either 64GB x 4 or 128GB x 2 setup.

 

[lvt]

There's 32mb built into the S11 controller which does not support an external dram module that I am aware of.
This is considered Dram-less as the 32mb does not offer much benefit.

That cache is SRAM cache, not DRAM.

 

[PhantomXT]

Can you post a photo of the back?

Can you post a photo of the back?

https://eplaza.waltonbd.com/index.php?route=product/product&path=240_508_509&product_id=4738

 

[PhantomXT]

Normall, on a card with 256GB like this, you have either 64GB x 4 or 128GB x 2 setup.

128GBx2 hynix HA7AG5KA0A

 

[PhantomXT]

That cache is SRAM cache, not DRAM.

So it has 32MB SRAM?

 

[lvt]

So it has 32MB SRAM?

Yes, as @popatim mentioned, the controller has 32MB of SRAM built-in.

It's not the proper DRAM cache that you asked, normally there is a dedicated DRAM chip on the PCB along the controller and the NAND chips.

 

[lvt]

@fahimsarker046 :

Here is the image of the SSD I currently have, you can see the 4 NAND chips (64GB x 4), the Phison controller and the 128MB DRAM chip.

 

[PhantomXT]

@popatim @lvt Thanks

 

[fzabkar]

IIUC, Phison's PS311-S11/S11T flash controllers incorporate an SDRAM controller. The SDRAM is external. The PS3111-S11T can run in either DRAM or DRAM-less mode, according to Phison's press release.

https://www.phison.com/en/company/n...troller-for-embedded-and-client-ssd-solutions

DRAM and DRAM-Less Support

 

[Maxxify]

The S11 does indeed have embedded SDRAM (DRAM), 32MB in capacity. However, according to its manual (M.2 variant) this is used as a write cache rather than for metadata (pp. 4-5, or 12-13/36). It should be considered DRAM-less for all practical purposes. As fzabkar states above, it has a DRAM controller (it has to for the embedded amount), so technically could support external DRAM, but never does.

 

[lvt]

IIUC, Phison's PS311-S11/S11T flash controllers incorporate an SDRAM controller. The SDRAM is external. The PS3111-S11T can run in either DRAM or DRAM-less mode, according to Phison's press release.

https://www.phison.com/en/company/n...troller-for-embedded-and-client-ssd-solutions

Yes a controller can run with or without DRAM, the OP simply wants to know if his SSD has DRAM cache.

 

[fzabkar]

The S11 does indeed have embedded SDRAM (DRAM), 32MB in capacity. However, according to its manual (M.2 variant) this is used as a write cache rather than for metadata (pp. 4-5, or 12-13/36). It should be considered DRAM-less for all practical purposes. As fzabkar states above, it has a DRAM controller (it has to for the embedded amount), so technically could support external DRAM, but never does.

Phison's block diagram shows Mask ROM, Data SRAM and Programmable SRAM. That's static RAM, not SDRAM. You don't need a controller to access SRAM.

http://www.users.on.net/~fzabkar/SSD/Phison/PS3111_block_diag.gif

 

[Maxxify]

All controllers have SRAM. SDR controller = DRAM controller. The use of this DRAM/SDR is detailed in the source I provided above but is integrated.

 

[fzabkar]

All controllers have SRAM. SDR controller = DRAM controller.

Yes, I am well aware of that. I was addressing this statement which is not supported by the block diagram:

The S11 does indeed have embedded SDRAM

 

[Maxxify]

Check my source above at the pages I list, or any number of products that say "integrated 32MB SDRAM"

If you want an official accounting I can ask Phison's product manager, but in his one article at TH he incorrectly stated this was 32MB of SRAM.

 

[NightHawkRMX]

You can physically see the lack of a dram chip, so no dram.

The controller will have SRAM cache similar to a CPU, but this is different from a dram cache.

 

[Maxxify]

It has both SRAM and integrated SDRAM (32MB). However, as stated, the SDRAM does not operate like DRAM on most SSDs (for metadata) but rather for small write caching.

 

[Maxxify]

You can physically see the lack of a dram chip, so no dram.

You can absolutely have DRAM on-package, but I agree there's clearly no external chip here. Although many products state 32MB of SDR. However from the S11 documents (I linked one above) it states this is utilized for write caching, so the point is moot.

tl;dr it's DRAM-less

 

[NightHawkRMX]

While possible, I have yet to see an SSD with dram on package, so I assume it is extremely uncommon.

 

[Maxxify]

It is, although the S11 manuals mention it directly. I believe the "32MB of SRAM" from some reviews (TH) is an incorrect reading of this. The S11 has SRAM, but also additionally can have 32MB of integrated SDRAM/DRAM, but for write-caching and not metadata. Since it has a SDR controller it could operate in a DRAM mode regardless. There are "BGA" SSDs that combine the controller and flash, etc., into one package, though.

I'll ask Chris the next time I get the chance. He and I were going back-and-forth on Reddit about their new E18 drive with 176L TLC from Micron and we talk in other social groups so I'll see what he has to say officially. However, no matter what this drive is DRAM-less by the definition of DRAM being used for metadata (in which case, it is 99% going to be external anyway).

 

[NightHawkRMX]

I have had 2 SKhynix OEM nvmes that remind me of that. One was 128gb with the lengths of a wifi card. The other one was a 256gb with standard m.2 2280 size and just tons of empty PCB.

https://ibb.co/89nCfCH

Both had a grand total of one single chip presumably with the nand, controller, and any cache involved Included. I assume they were dramless, but now this makes me wonder if they actually had/have dram in that package.

 

[Maxxify]

Yep, that's what I'm talking about, OEM drives with the BGA package like Samsung's PM991/PM991a (scroll down a bit). Usually these are DRAM-less but you see something similar on phones with embedded designs. An example of one with DRAM is the PM971: "features an extremely compact package that contains all essential SSD components including NAND flash memory, DRAM and controller."

It's possible the S11 situation is confused because reviewers got materials from Phison listing the 32MB of SDR when it might just be an optional feature. This still happens today, in fact very recently we were talking with Chris about the E18's configuration and there was confusion about the # of total cores involved due to how it is marketed.