Review Index:

Samsung 850 Pro 512GB Full Review - NAND Goes 3D!

Subject: Storage
Manufacturer: Samsung


Samsung has certainly been pushing the envelope in the SSD field. For the past two years straight, they have launched class leading storage products, frequently showing outside-the-box thinking. Their 840 PRO series was an impressive MLC performer to say the least, but even more impressive was the 840 EVO, which combined cost-efficient TLC flash with a super-fast SLC cache. The generous SLC area, present on each die and distributed amongst all flash chips within the drive, enabled the EVO to maintain PRO-level performance for the majority of typical consumer (and even power user) usage scenarios. The main win for the EVO was the fact that it could be produced at a much lower cost, and since its release, we've seen the EVO spearheading the push to lower cost SSDs.

All of these innovations might make you wonder what could possibly be next. Today I have that answer:

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If you're going "Hey, they just changed the label from 840 to 850!", well, think again. This SSD might have the same MEX controller as its predecessor, but Samsung has done some significant overhauling of the flash memory itself. Allow me to demonstrate.

Here's standard (2D) flash memory, where the charge is stored on a horizontal plane:

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..and now for 3D:

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The charges (bits) are not stored at the top layer. They are stored within all of those smaller, thinner layers below it. You're still looking at a 2D plane (your display), so here's a better view:

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Read on as we dive even deeper into this awesome new 3D flash technology!

Here's an evolution of old to new:

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The newer type of flash (second from left) is called Charge Trap Flash. It hadn't really caught on in the 2D world, but it works extremely well with the particular process Samsung has chosen.

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Building chips in this fashion is not exactly easy. Stacking a bunch of layers is not that big of a deal, but then etching deep holes through all layers, and then applying coatings from the inside-out, is a novel idea to say the least.

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The trick up Samsung's sleeve is that since they are stacking vertically, they don't need to pack things in so tightly on the horizontal plane. This enabled Samsung to take a step back on the lithography side of things, meaning V-NAND is made on a 30nm process. Note the above slide was from the first generation of mass produced V-NAND that appeared only in one of Samsung's prior enterprise products. That 24-layer V-NAND had 128Gbit per die, which is comparable to current gen 20nm planar NAND. This newer 32-layer V-NAND is made with a smaller die capacity of ~86Gbit, presumably because yields are tougher the more layers you add. This is no biggie, though, as the smaller die footpront helps Samsung fit more dies in a chip package, compensating for the difference. Smaller dies also translates to more dies per wafer. Despite the lower die capacity, this rearrangement should yield a net benefit in manufacturing cost.

Whew, that was a lot of tech talk. For those who have stuck with me through it all, I reward you with a video illustrating how it's done:

If that's not out-of-the-box thinking, I don't know what is! Now let's see how this puppy does in the benches!

June 30, 2014 | 11:22 PM - Posted by Thedarklord

Awesome read!

Very cool stuff, seems like the shift from 2D to 3D in process tech is shaping up to be a very cool thing, first CPU's, now SSD's, upcoming is the stacked ram on video cards.

I didn't see an ETA on these to market, any idea on availability?

June 30, 2014 | 11:32 PM - Posted by serpico (not verified)

I would hardly call intel's finfet technology 3d. I'm still waiting for the 3d cpu revolution. Heat dissipation, however, will not be easy for CPU's.

July 1, 2014 | 04:45 AM - Posted by arbiter

cpu's are at a very small nm size, not easy to get that heat outta there.

July 2, 2014 | 07:10 PM - Posted by Creator831 (not verified)

So far the release date is set to 21st July

June 30, 2014 | 11:26 PM - Posted by arbiter

Graph's on "PCMark Vantage and 7" page, is missing numbers on them.

July 1, 2014 | 01:34 AM - Posted by Allyn Malventano

Getting the figures all on the same chart and readable was overwhelming the chart. I'll tinker and see if we can get them all on there somehow.

July 1, 2014 | 12:43 AM - Posted by sixstringrick

Tech report needs to start the kill test on this drive. My guess would be 4PB, which is still ridiculous, and I'm probably underestimating it.

July 1, 2014 | 12:45 AM - Posted by sixstringrick

Also, 10 year warranty?! I think the 512 will find a good home in my Corsair Air 540

July 1, 2014 | 01:15 AM - Posted by Allyn Malventano

I'm sitting right next to Geoff (author of the first kill test piece). He says it 'will take too damn long' LOL. He's right.

July 1, 2014 | 08:52 AM - Posted by Pholostan

Lol indeed :)

SATA is too damn slow today. The express version seems like a clunky slapped together thing that I'm not sure I want. Like the M.2 some manufacturers put on their boards and make them SATA only, what a waste of space. We need multiple PCIe 3 or 4 lanes and NVMe.

July 2, 2014 | 11:29 PM - Posted by Steven Klein (not verified)

Does anybody sell such a drive today? I think the drive Apple uses in the current Mac Pro is a 4-lane. Anandtech benchmarked it at over 1000MB/sec!

(The iMac had 2 lanes for its SSD, and it still beats SATA III, though not by much.)

July 1, 2014 | 04:26 AM - Posted by arbiter

given 10 year warranty i would expect it would take a lot of data to kill the thing.

July 1, 2014 | 07:53 AM - Posted by Anonymous (not verified)

What hard drive were you using 10 years ago? Are you still using it now? Would you still use it now even if it worked?

I was using dual 36GB Raptors in RAID0 and I would not ever considering using those today. Too small, too slow. Ten years from now, we won't even care if our SSDs are still working.

July 1, 2014 | 10:04 AM - Posted by Anonymous (not verified)

I still have a Maxtor 6L040J2 spinning away in my low-traffic web server. It's easily ~10 years old. Loud as heck but still cranking away. I don't put anything critical on it any more though, despite SMART saying the drive's healthy.

July 1, 2014 | 11:22 AM - Posted by g.g (not verified)

If it's a low-traffic web server, wouldn't it work equally well from a humble SD flash card? :-)

July 1, 2014 | 03:18 AM - Posted by FAsic (not verified)

2X 256GB in raid 0 ?! :D

July 1, 2014 | 06:11 AM - Posted by razor512

How will the thinner layers impact write endurance?

Also, will overclocking the bus that the data controller is on, or overclocking the controller, improve the throughput for a single drive?

They should do a less involved endurance test, write to it but don't test the integrity until it reaches 1pb. At its write speed, it will not take too long, especially if there is no benchmark every 100 TB. Since the rated endurance is not always accurate, a test needs to be done.will this drive go beyond the rated endurance, or will it fail at around the 150TB rating (the 10 year warranty is also limited by it where after 150TB the warranty is void.

July 1, 2014 | 06:18 PM - Posted by Allyn Malventano

The claim is 10x the endurance, and that's considering the layer thickness. Since the cells are cylinders, there is more volume to store the charge, which is likely what lets them get better endurance.

Unless you can overclock the SATA bus itself, you're not going to see any improvement.

July 1, 2014 | 07:11 AM - Posted by Martin Trautvetter

This makes for a really nice last hurrah for SATA SSDs.

Cant wait to see what Samsung flew you out for!

July 1, 2014 | 11:01 AM - Posted by amadsilentthirst

Trying not to be too nerdy, but you have a rounding error in your 128GB pricing calculations.

You show the cheaper $129.99 costing more per GB
than the $130 original price.

1.015625 ($1.01/GB)
1.015546 ($1.02/GB)

Not sure why one was rounded up and the other rounded down, and while it really doesn't matter, it may suggest some laxness in your calculations which is not what you want on such a good review.

July 1, 2014 | 11:10 AM - Posted by Anonymous (not verified)

Who comments on the third significant digit being off by 1 on anything? Really is that important? lol

July 1, 2014 | 03:38 PM - Posted by Scott Michaud

Allyn wrote the original ($130) and, for some reason, rounded down. I did the update, because Allyn couldn't access his laptop. I used proper significant figure rules.

So, your answer? Two different people. I noticed Allyn's truncating, too, but left it as is.

July 1, 2014 | 11:13 AM - Posted by mAxius

ok i want this in sata express for my haswell 2011 build

July 1, 2014 | 11:52 AM - Posted by chongmagic

Was rapid mode enabled on the 840 Pro during the benchmarks?

July 1, 2014 | 12:47 PM - Posted by arbiter

If it was, the write and read speeds would been higher.

July 1, 2014 | 06:21 PM - Posted by Allyn Malventano

I don't test these SSDs using RAPID, since I'm testing the SSD, not the Samsung Magician software ability to cache data in RAM. It's really unnecessary interference, especially since performance for uncached areas is *lower* with RAPID enabled, due to the increased system overhead involved.

July 14, 2014 | 02:22 PM - Posted by PoobBubes

Would you recommend disabling RAPID for real world use?

July 1, 2014 | 01:43 PM - Posted by Rick Rodriguez (not verified)


Do you know if there is to be a enterprise version of this bad boy?

July 1, 2014 | 06:23 PM - Posted by Allyn Malventano

Yup! There's an 845DC PRO coming, which uses the MEX controller and V-NAND (but it's the older 24 layer stuff). More to follow on that as I'm working up a post from the events yesterday.

July 1, 2014 | 02:39 PM - Posted by Anonymous (not verified)

Still won't buy an SSD until under 25cents a gig.

There is no reason except for greed that they shouldn't be there right now and still be profitable to the manufacturer.

The premium is too damn high.

256gb is a joke for usability. Some games eat up 40+ gigs. That puts comfort use at 500gb or higher.

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