DRAM-less ssd

[SleepingGiant]

I do i put this hmmm...

How can you know a dram-less ssd from a complitly normal ssd with dram? For example when your in a store what do you look for in the packaging/box that it comes from.

 

I have tried looking it up on the manufacturers site but sadly i can't seem to find the buffer/cache/dram part of the specs.

[mariushm]

If you can't find that info, the SSD is probably DRAMless.

If you're really interested you can build yourself a list a ssd controller chips and you'll known which are completely dramless or which ones can work with or without dram.

[hojnikb]

Generally, cheaper drives are DRAMless. M.2 drives are easy to spot, because if you can see the drive, you can look for the dram chip.

 

Another option is to look for a review or at least a spec sheet. Even if it doesn't mention dram amount or presence, you can usually deduct that by the controller type (usually there are separate controller designs for dram or dramless ssds).

[SleepingGiant]

16 hours ago, mariushm said:

If you can't find that info, the SSD is probably DRAMless.

If you're really interested you can build yourself a list a ssd controller chips and you'll known which are completely dramless or which ones can work with or without dram.

@mariushmWait i'm getting confused here. I thought dram and controllers are different

[SleepingGiant]

8 hours ago, hojnikb said:

Generally, cheaper drives are DRAMless. M.2 drives are easy to spot, because if you can see the drive, you can look for the dram chip.

 

Another option is to look for a review or at least a spec sheet. Even if it doesn't mention dram amount or presence, you can usually deduct that by the controller type (usually there are separate controller designs for dram or dramless ssds).

@hojnikbCould you give me a sample on how to use the controller info to see if it has dram?

[hojnikb]

4 hours ago, SleepingGiant said:

@hojnikbCould you give me a sample on how to use the controller info to see if it has dram?

An easy example: SM2258XT has no dram and it's bigger brother SM2258 does.

 

Same with Phison controllers (S11 does not, S10 does etc..)

[SleepingGiant]

On 7/30/2019 at 2:38 PM, hojnikb said:

An easy example: SM2258XT has no dram and it's bigger brother SM2258 does.

 

Same with Phison controllers (S11 does not, S10 does etc..)

@hojnikb I see......

Hope every controller manufacturer has this table

Edited July 31, 2019 by SleepingGiant

[mariushm]

Not always the case.

Depends on how the manufacturer of ssd controller makes the choice.

Some have different designs, one with ddr controller, one without, others may simply do one design and disable the ddr controller to create two versions - or they may sell the chips with faulty ddr controllers as "no ddr controller chip"

 

It can cost lots of money (let's say 300k to half a million) to make the "master' from which a chip can be made in volume. So some companies may not want to pay this much for each of the two designs.

However, some may do it if they can actually make the physical chip smaller by removing the ddr controller part, because then they can actually get more chips out of a wafer (a silicon disc from which chips are cut out) so they recuperate that initial investment by getting more chips out.

Sometimes though you get to the point where you can't really shrink the actual chip footprint due to the number of i/o pins and other stuff.

 

Some SSD controller makers will work first on dramless controllers because it's higher volume, higher demand, so they'll recuperate the money invested faster.

With the profits from these, they can work on the higher end chips without risking bankruptcy.

 

[hello_there_123]

https://docs.google.com/spreadsheets/d/1B27_j9NDPU3cNlj2HKcrfpJKHkOf-Oi1DbuuQva2gT4/edit?usp=sharing

[hojnikb]

1 hour ago, mariushm said:

Not always the case.

Depends on how the manufacturer of ssd controller makes the choice.

Some have different designs, one with ddr controller, one without, others may simply do one design and disable the ddr controller to create two versions - or they may sell the chips with faulty ddr controllers as "no ddr controller chip"

 

It can cost lots of money (let's say 300k to half a million) to make the "master' from which a chip can be made in volume. So some companies may not want to pay this much for each of the two designs.

However, some may do it if they can actually make the physical chip smaller by removing the ddr controller part, because then they can actually get more chips out of a wafer (a silicon disc from which chips are cut out) so they recuperate that initial investment by getting more chips out.

Sometimes though you get to the point where you can't really shrink the actual chip footprint due to the number of i/o pins and other stuff.

 

Some SSD controller makers will work first on dramless controllers because it's higher volume, higher demand, so they'll recuperate the money invested faster.

With the profits from these, they can work on the higher end chips without risking bankruptcy.

 

DRAMless controllers almost always have a different part number. It doesnt really matter from what die a particular controller is carved from for the end consumer.

[SleepingGiant]

10 hours ago, hello_there_123 said:

https://docs.google.com/spreadsheets/d/1B27_j9NDPU3cNlj2HKcrfpJKHkOf-Oi1DbuuQva2gT4/edit?usp=sharing

@hello_there_123 this is really helpful. Thank you