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Samsung 850 EVO and Pro 2TB SATA SSD Review - Multi-terabyte Consumer SSDs Are Here!

Subject: Storage
Manufacturer: Samsung

Introduction, Specifications and Packaging


Where are all the 2TB SSDs? It's a question we've been hearing since they started to go mainstream seven years ago. While we have seen a few come along on the enterprise side as far back as 2011, those were prohibitively large, expensive, and out of reach of most consumers. Part of the problem initially was one of packaging. Flash dies simply were not of sufficient data capacity (and could not be stacked in sufficient quantities) as to reach 2TB in a consumer friendly form factor. We have been getting close lately, with many consumer focused 2.5" SATA products reaching 1TB, but things stagnated there for a bit. Samsung launched their 850 EVO and Pro in capacities up to 1TB, with plenty of additional space inside the 2.5" housing, so it stood to reason that the packaging limit was no longer an issue, so why did they keep waiting?

The first answer is one of market demand. When SSDs were pushing $1/GB, the thought of a 2TB SSD was great right up to the point where you did the math and realized it would cost more than a typical enthusiast-grade PC. That was just a tough pill to swallow, and market projections showed it would take more work to produce and market the additional SKU than it would make back in profits.

The second answer is one of horsepower. No, this isn't so much a car analogy as it is simple physics. 1TB SSDs had previously been pushing the limits of controller capabilities of flash and RAM addressing, as well as handling Flash Translation Layer lookups as well as garbage collection and other duties. This means that doubling a given model SSD capacity is not as simple as doubling the amount of flash attached to the controller - that controller must be able to effectively handle twice the load.

With all of that said, it looks like we can finally stop asking for those 2TB consumer SSDs, because Samsung has decided to be the first to push into this space:

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Today we will take a look at the freshly launched 2TB version of the Samsung 850 EVO and 850 Pro. We will put these through the same tests performed on the smaller capacity models. Our hope is to verify that the necessary changes Samsung made to the controller are sufficient to keep performance scaling or at least on-par with the 1TB and smaller models of the same product lines.

Read on for the full review!


850 Pro:

  • NAND: Samsung 32-layer 3D VNAND
  • Unformatted Capacity: 128GB / 256GB / 512GB / 1TB / 2TB
  • Max Sequential Read: 550 MB/s
  • Max Sequential Write (256GB and up): 520 MB/s
  • Max Random Read QD32: 100,000 IOPS
  • Max Random Write QD32: 90,000 IOPS
  • Form Factor: 7mm high 2.5”
  • Interface Type: SATA 6.0 Gb/s (SATA 3)
  • Endurance (512GB and up): 300TBW @ 80 GB/day
  • Warranty: 10 years

850 EVO:

  • NAND: Samsung 32-layer 3D VNAND
  • Unformatted Capacity: 120GB / 250GB / 500GB / 1TB / 2TB
  • Max Sequential Read: 540 MB/s
  • Max Sequential Write: 520 MB/s
  • Max Random Read QD32 (500GB and up): 98,000 IOPS
  • Max Random Write QD32 (500GB and up): 90,000 IOPS
  • Form Factor: 7mm high 2.5”
  • Interface Type: SATA 6.0 Gb/s (SATA 3)
  • Endurance (500GB and up): 150TBW @ 80 GB/day
  • Warranty: 5 years

The stated specs for the 2TB models identically match that of the 1TB models of those same product lines. The only difference elsewhere in the specs was the controller type used (more on that on the next page).


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Samsung has continued using the standard 850 series packaging for both of these new higher capacity models.

Video News

July 6, 2015 | 10:17 AM - Posted by Anonymous (not verified)

At long last! $800 is about what I was hoping for (as a starting point anyway). We need more of these!

July 7, 2015 | 02:57 PM - Posted by LazyLizard

yeah cant wait to have all my storage behind my motherboard and not messing with my airflow. :)

July 7, 2015 | 03:35 PM - Posted by BBMan (not verified)

While I get it, the price was a deal breaker for me. It scales pretty much directly with their 1TB version. When the 1TBs came out, they were a noticeably better bang for the (GB/)buck.

Here's hoping competition becomes more fierce and larger, because I ain't touchin' this at $800-1000. I have a feeling this may be very temporary price point.

July 6, 2015 | 10:28 AM - Posted by Gadgety1 (not verified)

Nice size. Just hope the EVO doesn't go slow on me like the 840 did. Firmware upgrade is just a temporary band aid. I'd like to see a rebate for a unit instead: Hand in your old 840 EVO with your new 2TB purchase, and get $100 off. In addition, perhaps a repeat review of the EVO unit will be necessary a year from now to draw a conclusion.

July 6, 2015 | 11:50 AM - Posted by Allyn Malventano

This is a different type of flash entirely (VNAND). Also, it appeared Samsung delayed the 850 EVO launch right when the 840 EVO slow down issue was popular. I'd guess this was to make sure their new product wouldn't have the same issue.

July 6, 2015 | 12:53 PM - Posted by Anonymous (not verified)

Except its not a band-aid fix? Allyn has stated multiple times on Overclock that it actually fixes the issue with the 840 EVOs and the "band-aid fix" thing arised out of bad wording in the initial announcement of the new FW.

July 6, 2015 | 10:29 AM - Posted by Anonymous (not verified)

Great drive; no doubt. Here are my main sticking points. One, with the latest kerfuffle about NANDs losing integrity if not powered up within a certain time is concerning (not that SSDs are usually used as long term storage without power). Two, these don't address the elephant in the room NVMe. With NVMe poised to take the baton why invest in these? My next SSD will be NVMe not SATA.

July 6, 2015 | 11:52 AM - Posted by Allyn Malventano

For the NAND thing, don't believe the one blog about an SSD losing data in one week. That was more likely a defective SSD.

NVMe is great, but these will fit into the many laptops that are not NVMe capable.

July 7, 2015 | 08:04 AM - Posted by Anonymous (not verified)

True, they'll fit into many laptops, but most new laptops today have eschewed the 2.5 versions for the m.2. form factor as thinner laptops can be made, not to mention the massively increased performance on x4 slots. I think the writing is on the wall with the current SATA line. Intel has already demonstrated (as has Samsung with the 951) that SATA with its platter favoritism is too old and no longer is a viable solution for NAND based solutions.

July 6, 2015 | 10:58 AM - Posted by mangel (not verified)

Wonder how they look in RAID. Keep 4TH mechanical drive as a backup and use 2 of these as data drive with SM951 as primary drive. That is expensive though.

July 6, 2015 | 11:31 AM - Posted by mangel (not verified)

Meant 4TB not 4TH

July 6, 2015 | 11:11 AM - Posted by anon (not verified)

I've always wondered, how exactly does the SSD warranty work. Is it just for parts and labor or does the drive continence factor in, like for example if (you are an idiot and) you have your all your wedding photos on that drive without backup and the drive crashes before you can print them, OR say you are writing an educational text book and the drive crashes loosing all your "Revisions" notes, destroying hours and hours or days or weeks of hard work, is the drive manufacture liable for the monetary value of said photos? Or what if the drive crash causes surge damage to the mother board or other components (dont know if that is still a problem but it usta be)? Does that 5/10 year warranty make them liable for all the problems that would be created by a failing of that warranty, or is it simply "The physical drive will be replaced sorry bout the rest."

And also 2tb SSD....... nice!

July 6, 2015 | 11:47 AM - Posted by Allyn Malventano

There is generally no data recovery portion of an SSD warranty. If they have no backup, it's up to the customer to send it off to a data recovery place and try to get the data back *before* doing the simple RMA swap with the seller. Also, sellers will still accept the return if it has been opened by a data recovery place (they mark the drive as such). Same applies to hard drives.

July 9, 2015 | 12:08 AM - Posted by dwj7738

RMA is a one for one exchange as always.. Data Recovery is and has always been a responsibility of the user. That is what backup's are for.

July 6, 2015 | 11:16 AM - Posted by OldLadies (not verified)

Finally! I purchased 2 1TB 840 EVO's for about $1000 so 2TB for $800 is a decent price but I suspect it will come down in price even more with sales and competition.

Been HDD free for over a year. I will wait for this to come down in price a bit more.

July 6, 2015 | 11:48 AM - Posted by Allyn Malventano

If you have those two in RAID-0, you're still getting 2x the performance of even the 2TB model, as a single SATA channel is clearly the bottleneck for such a large capacity SSD.

July 6, 2015 | 12:14 PM - Posted by Soloasylum

Guess I'll be buying 2 of these when my credit card empties.. Already filled the 2 1tb 850 evos with flight simulator x and steam sales.

Bye bye money.

July 6, 2015 | 12:49 PM - Posted by Allyn Malventano

Get another pair of 1TB's and quad RAID-0 it? (Also, back up!)

July 6, 2015 | 05:28 PM - Posted by Soloasylum

That might be a possibility if they drop the price of the 1TB's to a reasonable degree. If there is only a $40-50ish difference between the 1TB and 2TB, I can't say it would be worthwhile just to save $100ish.

July 6, 2015 | 05:50 PM - Posted by BillDStrong

Naw, he should just get 4 of these. Then Quad RAID it. Why settle for less? :)

July 6, 2015 | 02:34 PM - Posted by Anonymous (not verified)

I hope they won't get rid of their 128gb drives like how 64gb drives are disappearing, they worked great for boot drives esp for Linux distros which are rather small.

Anyway, exciting news hopefully prices keep getting driven down I want to replace my vertex 3 128gb next year.

July 6, 2015 | 02:47 PM - Posted by Bleomycin (not verified)

It's great to finally see 2TB capacities at reasonable prices! Unfortunately I won't be touching anything from Samsung until they address their TRIM related data loss issues:

July 6, 2015 | 03:21 PM - Posted by Anonymous (not verified)

Do you use a linux server in RAID on EXT4? If the answer to this question is no, then you have nothing to worry about with TRIM.

This is one blog reporting an issue they've noticed in their systems. No one else has reported anything similar. TRIM on SSDs have been working fine in Windows and OSX. Most of the listed Samsung SSDs have been out for several years. If there was a TRIM data loss issue with those drives, i'm pretty sure there would be widespread reporting on it.

The first site to report on this was Tech Report, and they reported it as if everyone's Samsung SSD is gonna lose data, when its simply not true. In reality, as i stated above, it was one blog. If you look at Tech Report's history on reporting Samsaung SSD "issues", they seem to live off spreading widespread panic.

July 6, 2015 | 03:33 PM - Posted by Allyn Malventano

Yeah, that is specific to queued TRIM, and is not an issue if you are on the current Kernel since they have that SSD blacklisted now. Also note that Samsung is not the only brand of SSDs present on that blacklist.

July 6, 2015 | 03:44 PM - Posted by Anonymous (not verified)

The Queued TRIM issue is a separate issue from what Algolia is reporting.

Algolia specifically states that "UPDATE June 16:
A lot of discussions started pointing out that the issue is related to the newly introduced queued TRIM. This is not correct. The TRIM on our drives is un-queued and the issue we have found is not related to the latest changes in the Linux Kernel to disable this features."

July 6, 2015 | 04:13 PM - Posted by Allyn Malventano

Yes, but the thing is there are a lot of these drives out in the wild, and we would be seeing a lot of users with corrupted partitions or lost data if what they said in that update applied to everyone with these drives.

July 6, 2015 | 04:29 PM - Posted by Anonymous (not verified)

I wrote the post with the mention of tech report.

I agree with you. It is annoying how some people are taking this as fact and are jumpin the bandwagon. Like i said, tech report's article made it sound like is a fact that everyone is affected by this, when its just the algolia ppl who are affected.

July 6, 2015 | 10:00 PM - Posted by PapaDragon

Awesome, cant believe I'm seeing this capacity now. When I move to a 4k workflow, I will definitely consider these drives! Thanks 4 the review Allyn.

July 7, 2015 | 02:26 AM - Posted by Anonymous (not verified)


Intro MSRP's

850 Pro 2TB*: $1000 ($0.49/GB*) (Amazon)
850 EVO 2TB: $800 ($0.40/GB) (Amazon)"

The Amazon links don't go to any product page. The drives don't currently exist on Amazon's website, so what are the links for?

July 7, 2015 | 02:38 PM - Posted by Allyn Malventano

The links are to the search as they have not yet been listed for sale. They also include our affiliate code, which helps benefit the site should someone make a purchase as a result of using them.

July 8, 2015 | 11:56 PM - Posted by Dark_wizzie

Hey Allyn,

Is there an article that describes the differences between each of your SSD benchmarks? File server vs web server, etc. And latency? I'm not sure how that plays into performance either.

Also, it would be great if there was an article for traced-based analysis of gaming loads, or if you could recommend a program for us to test it with our own games. I was wondering if the faster SSDs (Intel 750, Samsung sm951 Nvme) make any difference at all for something like Skyrim with a million mods, running around outside... I think the CPU usage hits 25% during cell loading and I think the game might actually be CPU bottlenecked with 850 Pro since it's Sata.

Or am I spitting out nonsence?

Anyways, keep up the good work. :p

July 9, 2015 | 08:53 AM - Posted by Allyn Malventano

We don't spell out the exact workloads in order to keep these tests 'ours', but they are simply based on their descriptor (file server, etc).

We used to use PCMark for the trace based stuff, but it got to the point where there was little to no difference across batches of SSDs - even SSDs that we knew would be performing differently based on their other specifications / benchmark results. The issue was that PCMark is weighing the time where the storage is idle too heavily in its results. An extra 10 seconds of loading time out of a 10 minute gamimg session doesn't add a large percentage to the total, but a gamer is actually *waiting* on that load and would be much more inclined to note the performance difference. PCMark also does not correct or test for SSDs being filled to various capacities. We're working on something better, but we're not there yet.

As far as 'CPU bottlenecking because of SATA', that shouldn't really be a thing with a single SATA SSD (unless the game is requesting >100k IOPS, which is highly unlikely). It's more likely that the game is sharing a thread to both load and process the data being read. If that game is pegging a core when doing so with a SATA SSD, it's not likely to be any faster if loading from a different source. Situations like this are what would make SSD testing very game / CPU speed specific, and would rapidly add too many variables to justify the testing, as just testing some level loads with some games would not paint the full picture for someone on a slower CPU. That CPU dependency is also why I see trace-based game load testing as an 'incorrect' test. None of the trace playback utilities can emulate the actual game load thread's CPU dependency. An SSD 750 may play back a trace at 2x the speed of a SATA SSD, but if the game was actually CPU bottlenecked on the SATA SSD, it would not go any faster on the PCIe SSD when retested with the game itself.

July 9, 2015 | 07:24 PM - Posted by Dark_wizzie

Hey Allyn,
Thanks for the reply.

When I was talking about cell loading in Skyrim causing 25% CPU usage, it wasn't a suggestion for a test because as you said, it would be way too hard to test. I was just curious whether I would see a gain if I decide to get an NVMe drive for myself.

So if that one maxed out single core is at 25%, it must be sending requests to the SSD and processing the rest of the game and whatever it gets from the SSD all in that one core, leading to the CPU core being pegged, totally busy. So then in theory an NVMe SSD would lower the CPU usage for the requests to the SSD so that the game has more CPU cycles to do its other tasks while loading? That would... in theory... mean that the game will load faster.

In theory, of course. :)

Correct me if I'm wrong, but wouldn't traced based analysis help us see what type of loads a game demands from an SSD? For example, game A might request a ton of random 4k reads, game B might want 512kb random reads, but when starting the game up, request sequential reads, and saving a save file would mean doing a bunch of random and sequential writes, etc. I guess the data doesn't really matter in the real world, and this would be more for curiosity's sake.

July 9, 2015 | 10:44 AM - Posted by Doeboy (not verified)

2 TB is the sweet spot for primary hard drive. Unfortunately, it's still too expensive IMHO compared to SATA so I'll wait until it's down to $300. SATA is still good enough for me.

July 9, 2015 | 03:13 PM - Posted by DIYEyal

If I'm spending $800 on an SSD, I would want a superfast one like the Intel 750 series with a lower capacity. Also, I don't know about most people here, but I wouldn't be able to fit my steam library in a 2TB drive.. If I had two of these I would be able to fit most of my games.. But I'm okay with having most of my games on HDDs and only some of them on my SSD.
This could be really nice for laptops that don't have mSATA or M.2...

Still a hard sell for $800 which is more than most people's PCs.

I still think SSDs can't fully replace a hard drive yet, they are just not cheap enough. They have come a long way, but we need more!

July 10, 2015 | 11:02 AM - Posted by veritron (not verified)

If I was going to pay a grand for an ssd I'd much rather get an Intel 750 series 1.2TB.. at least I'd get a noticable performance boost along with the capacity upgrade.

December 13, 2015 | 12:54 AM - Posted by Anonymous (not verified)

Did Samsung ever explain/fix the slow I/O Meter performance you show in your July review of the 2TB EVO at low queue depth? Is it now equivalent to the PRO in low queue depth performance? Thanks.

January 18, 2016 | 11:05 AM - Posted by Anonymous (not verified)

Hi there

Thanks for this awesome benchmark! I'm also very interested to know if you have heard something from Samsung about the slow I/O Meter performance you show in your July review of the 2TB EVO?

Thanks a lot for your time.

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