Review Index:

V-NAND Showdown - Samsung 850 EVO V1 and V2 Compared - 32 (V2) vs. 48 (V3) Layer Flash

Subject: Storage
Manufacturer: Samsung


Since Samsung’s August 2015 announcement of their upcoming 48-layer V-NAND, we’ve seen it trickle into recent products like the SSD T3, where it enabled 2TB of capacity in a very small form factor. What we have not yet seen was that same flash introduced in a more common product that we could directly compare against the old. Today we are going to satisfy our (and your) curiosity by comparing a 1TB 850 EVO V1 (32-layer - V2) to a 1TB 850 EVO V2 (48-layer - V3).


While Samsung has produced three versions of their V-NAND (the first was 24-layer V1 and only available in one of an enterprise SSDs), there have only been two versions of the 850 EVO. Despite this, Samsung internally labels this new 850 EVO as a 'V3' product as they go by the flash revision in this particular case.

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Samsung’s plan is to enable higher capacities with this new flash (think 4TB 850 EVO and PRO), they also intend to silently push that same flash down into the smaller capacities of those same lines. Samsung’s VP of Marketing assured me that they would not allow performance to drop due to higher per-die capacity, and we can confirm that in part with their decision to drop the 120GB 850 EVO during the switch to 48-layer in favor of a planar 750 EVO which can keep performance up. Smaller capacity SSDs work better with higher numbers of small capacity dies, and since 48-layer VNAND in TLC form comes in at 32GB per die, that would have meant only four 48-layer dies in a 120GB SSD.

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Samsung's 48-Layer V-NAND, dissected by TechInsights
(Similar analysis on 32-Layer V-NAND here)

Other companies have tried silently switching flash memory types on the same product line in the past, and it usually does not go well. Any drops in performance metrics for a product with the same model and spec sheet is never welcome in tech enthusiast circles, but such issues are rarely discovered since companies will typically only sample their products at their initial launch. On the flip side, Samsung appears extremely confident in their mid-line flash substitution as they have voluntarily offered to sample us a 1TB 48-layer 850 EVO for direct comparison to our older 1TB 32-layer 850 EVO. The older EVO we had here had not yet been through our test suite, so we will be comparing these two variations directly against each other starting from the same fresh out of the box and completely unwritten state. Every test will be run on both SSDs in the same exact sequence, and while we are only performing an abbreviated round of testing for these products, the important point is that I will be pulling out our Latency Percentile test for detailed performance evaluation at a few queue depths. Latency Percentile testing has proven itself far more consistent and less prone to data scatter than any other available benchmark, so we’ll be trusting it to give us the true detailed scoop on any performance differences between these two types of flash.

Read on for our comparison of the new and the old!
(I just referred to a 3D Flash part as 'old'. Time flies.)

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March 18, 2016 | 09:21 AM - Posted by Anonymous (not verified)

Excellent review as always.

Please do the same comparation with the 250 and 500 GB :I think this are the most popular capacity

March 18, 2016 | 09:38 AM - Posted by marian4q

Great review

March 18, 2016 | 10:17 AM - Posted by ryanbush81

Very good. I feel way better about my purchases knowing that PCPER is there to hold these manufactures accountable for their products.

Keep up the great work guys!

March 18, 2016 | 12:41 PM - Posted by Xebec

Thanks Allyn! Always appreciate these details!

March 18, 2016 | 01:37 PM - Posted by sensacion7

As always, a great review from Alyn thanks


March 18, 2016 | 02:27 PM - Posted by CB (not verified)

Great review. Love that you went the extra mile to get this in depth technical knowledge.

Is the 48-layer V-nand going to be used in all capacities?

How can one tell which one they have or purchase?

March 18, 2016 | 06:41 PM - Posted by Allyn Malventano

Not sure on packaging differences for the V2 (more to follow there).

48-layer will replace 32-layer in all capacities of the EVO (so far), but they are dropping the 120GB, most likely since it could not maintain expected performance with only four dies. 120GB is now covered by the 750 EVO.

March 20, 2016 | 03:03 AM - Posted by Krutou (not verified)

Any idea when the V2 version will roll out to retailers?

March 18, 2016 | 02:51 PM - Posted by Kevin (not verified)

Yes I would like to know also how you can tell which one you have. I'm looking at an 850 evo I bought a few weeks ago and have not installed yet.

March 18, 2016 | 04:36 PM - Posted by D1RTYD1Z619

Allyntek has the best ssd reviews

March 18, 2016 | 07:26 PM - Posted by MrTbagz (not verified)

on the next podcast please discuss the news story about Google's SSD Study. They found high-end SLC drives are no more reliable that MLC drives. They also found SSDs fail at a lower rate than disks, but Uncorrectable Bit Error Rate is higher. thx, do a search for 'google ssd study' for more info

March 19, 2016 | 02:28 PM - Posted by Allyn Malventano

I've read the study, and they are correct in how these failures happen, but their gear is not comparable to the consumer products that we test. As an example, Intel Enterprise SSDs (S3700) use different firmware that will intentionally brick them when certain errors are detected, while that same controller with consumer model firmware (SSD 730) will do its best to error correct and push on. Enterprise side does this because it is easier for them to just swap a drive, rebuild, and get on with their day. Enterprise settigns are more tolerant of errors in favor of higher / more consistent performance.

March 20, 2016 | 07:24 PM - Posted by Glaring_Mistake (not verified)

But weren't they also prone to silent errors meaning that they were never reported?

March 18, 2016 | 09:22 PM - Posted by Gamesing (not verified)

Is there a possibility that you could do a three drive Raid 0 test for speed and heat the way you did for your Triple M.2 Samsung 950 Pro Z170 PCIe NVMe RAID test.

Also, do know if Intel is going to change their controller for M.2 and SATA so that you do not loose any SATA ports when using M.2 ?

March 19, 2016 | 02:31 PM - Posted by Allyn Malventano

Currently Z170 trades M.2 for a pair of SATA. Some motherboards can arrange the lanes such that one M.2 can be used with no impact on SATA lanes (but the next M.2 will take four).

For a SATA RAID test, we don't have three of any sufficiently speedy idential SATA models on hand, but I can say that the scaling results tend to be similar. SATA just runs at a slower bus speed, but the IOPS scales similarly.

March 18, 2016 | 11:03 PM - Posted by Anonymous (not verified)

Great stuff, thanks!

March 18, 2016 | 11:23 PM - Posted by MRFS (not verified)



March 19, 2016 | 03:01 AM - Posted by khanmein (not verified)

@Allyn Malventano i confused. which one model version is MLC??? thanks



March 19, 2016 | 02:32 PM - Posted by Allyn Malventano




March 20, 2016 | 11:56 PM - Posted by khanmein (not verified)

thanks boss.

March 19, 2016 | 11:30 AM - Posted by Anonymous (not verified)

As long they keep their prices competitive , looks like I'll keep buying. Altho in my experience i swapped a 120gb 840 evo for a 120 850 evo, boot drive, and foubd the 850 slower. And thats just by getting the microsoft flag on screen. Migration done by samsung software. Weird eh?

March 19, 2016 | 02:33 PM - Posted by Allyn Malventano

Yeah something weird is going on there, because 850's walk all over 840's generally.

March 20, 2016 | 03:06 AM - Posted by Anonymous (not verified)

Until the 500GB and 250GB versions are tested and compared I don't see the the guarantee that the 1TB version would be indicative of no performance loss.

Samsung's controller is likely optimized for 4 dies per channel with 8 channels. This is why when you look at V1 500GB and 1TB comparisons the performance is nearly the same (including official specs) as the 500GB already has the 32 dies necessary for saturation. Whereas there is a drop off in write performance moving to 250GB due to the drop off to 16 dies.

So we would need to see what happens with the 500GB and 250GB versions due to the now lower number of controllers. Do they actually match the performance of their V1 counterparts? I'd say it's interesting that they chose to sample the 1TB V2 with it's 32 dies.

March 21, 2016 | 12:54 PM - Posted by Allyn Malventano

It's not about the number of dies per controller as much as it is about the TLC write speed of those individual dies. You are correct that the TLC write speed of a 250GB V1 vs. V2 may be different, but in practical use, these consumer drives almost never operate at TLC speeds (How often does any typical consumer write >3GB of data at >270 MB/s?).

March 22, 2016 | 03:41 PM - Posted by Mr.Meth

Great review as always guys !!

March 26, 2016 | 04:56 PM - Posted by nobody (not verified)

Just for reference, the SSDs V1 and V2 have different P/N:

V1: MZ7LE1T0
V2: MZ7LN1T0

Maybe you people can check if the SSD that you own have the same letter.

See yaa..

March 28, 2016 | 11:26 AM - Posted by Magistar (not verified)

This short review does not seem account for the TurboWrite technology. Basically Turbowrites diminishes the meaning of basic benchmarks like Atto because you will be testing the fast SLC portion only. In such tests even the 250 GB model performance identical to the larger models.

The real question here is; what happens to performance consistency with this new v-nand.

After all benchmarks have showed gaps of over 500% between the 250 GB and 1 TB model in scenario's where the SLC buffer is already full. In stuff like Atto there was no difference to begin with.

April 4, 2016 | 08:47 AM - Posted by Anonymous (not verified)

Hi there,

Can anyone tell me where to purchase these new 48-layer V-NAND drives? I've looked on Amazon and it seems they are still selling the 32 - layer versions. Anyone got a link (specifically for the 1Tb model)??

Thanks in advance.

May 2, 2016 | 09:00 PM - Posted by Dzezik (not verified)

the 48 layer is not better than 32.
it uses less power this is the only advantage
performance is similar
but the consistency of performance is worst
and the endurance is also worst
going to more layers is only because of efficiency

I can tell You I only buy god old 34nm SLC
and it outperforms any MLC TLC including 3D V-NAND.
SLC You can buy 100GB SSD starting from $100 and dont bother the performance at all and forget what is consistency and endurance.
MLC TLC and V-NAND was created only because of efficiency and low cost. SLC is still the best in performance class.

May 2, 2016 | 08:51 PM - Posted by Dzezik (not verified)

the first version 24 layer was used in two models:
SV843 and 845DC PRO.
they differ only in overprovisioning and price
SV843 was only 960GB 7% OP
845DC Pro was max 800GB 28% OP
moving from 7% to 28% in general it doubles the steady state random write twice and extends endurance twice.
the biggest improvement cames not from moving 24 to 32 layer but
moving from 300MHz MDX to 500MHz MHX
the 48 layer uses even newer controller

February 3, 2017 | 09:42 AM - Posted by Jose (not verified)

Does anyone know if the performance degradation issue that affected the 840 evo is present in the 850 evo?

September 1, 2017 | 03:15 PM - Posted by Shinjin (not verified)

Does anyone know when the 64 layer TLC available for EVO 850?

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