Review Index:

Samsung 840 EVO 500GB and 1TB Full Review - TurboWrite TLC

Subject: Storage
Manufacturer: Samsung

Introduction and Specifications


Last week, Samsung flew a select group of press out to Seoul, Korea. The event was the 2013 Samsung Global SSD Summit. Here we saw the launch of a new consumer SSD, the 840 EVO:

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This new SSD aims to replace the older 840 (non-Pro) model with one that is considerably more competitive. Let's just right into the specs:

Read on for our full review of the 500GB and 1TB models of Samsung's new SSD!


The new 840 EVO employs Samsung's 'MEX' controller, where the 840 and 840 Pro used 'MDX' and the 830 Series used 'MCX':

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From this slide we can tell the 840 EVO is employing the same TLC flash used in the older 840. The difference here being this new flash is 19nm as compared to the 21nm flash used in the older 840 and 840 Pro.

Specifications and TurboWrite:

Here are the throughput specs, starting off with the main differences between the 840 and the 840 EVO. Note the increased write specs:

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Ok, the speeds are much quicker, even though the flash is still TLC and even on a smaller process. How does it pull off this trick? Tech that Samsung calls TurboWrite.

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A segment of the TLC flash is accessed by the controller as if it were SLC flash. This section of flash can be accessed (especially written) much faster. Writes are initially dumped to this area and that data is later moved over to the TLC area. This happenes as it would in a normal write-back cache - either during idle states or once the cache becomes full, which is what would happen during a sustained maximum speed write operation that is larger than the cache capacity. Here is the net effect with the cache in use and also when the cache becomes full:

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For most users, even the smallest cache capacity will be sufficient for the vast majority of typical use. Larger caches appear in larger capacities, further improving performance under periods of large write demand. Here's the full spread of cache sizes per capacity point:

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We will take a close look at how this cache interacts with performance in the pages to come.

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July 25, 2013 | 09:34 AM - Posted by Mark Strong (not verified)

Thank you for the quick review sir. Personally I would call this a no question automatic upgrade for a new PC build. I'm interested to hear your thoughts on where this stacks up in the grand scheme of things.

July 25, 2013 | 10:02 AM - Posted by Allyn Malventano

If the pricing holds (and that's a big IF since I have yet to see sub-$1/GB pricing hold), the EVO will become my default recommendation for everything but the most demanding enterprise use.

July 25, 2013 | 10:38 AM - Posted by Mark Strong (not verified)

Then let us hope with fingers crossed that the price roughly holds (within 10 - 20 dollars). Much appreciated sir.

July 25, 2013 | 11:14 AM - Posted by grommet

I didn't see in the article when these would be available- did I miss it, or are they not saying yet?

August 12, 2013 | 12:52 AM - Posted by Allyn Malventano

No hard date, but I'd imagine as quickly as they can get them out there.

July 25, 2013 | 12:44 PM - Posted by Thedarklord

Great review.

As someone who is about to jump onto the SSD train;

1)It looks like several SSD makers are releasing new products now/very soon (so is it better to wait?)

2)I personally like the Corsair lineup, anyone heard anything if they are exiting the market?, seems like their SSD market is getting scarce.

, Thanks

July 25, 2013 | 01:30 PM - Posted by Ram Rangaswamy (not verified)

Allyn Malventano: The last line of the article says "...Samsung 840 ECO..." instead of EVO.

Otherwise, love the article and insight!

July 25, 2013 | 06:01 PM - Posted by Tad (not verified)

LOL PCMO5? What the hell? and Iometer 2006? ROFLSAUCE! Its like I ran into an '80's website. Does your SSD wear parachute pants too?

July 26, 2013 | 01:23 PM - Posted by Photonboy (not verified)

If a tool works to accurately assess a product, why does it have to be made very recently?

An older product is also well understood and allows accurate comparisons to previous products that also tested with the same tools.

August 12, 2013 | 12:50 AM - Posted by Allyn Malventano

^ this.

July 29, 2013 | 11:54 AM - Posted by Moochacho (not verified)

Is there any benefit these days (performance or stability) to having one SSD for OS, another for programs and a third for data? Back in the day I used to have the OS on its own partition or even different drive, so it wouldn't get all fragged up. I currently have a 120GB OCZ Vertex3 for OS, 1TB Samsung Spinpoint for progs and 500GB WD Black for data and trying to eliminate spinning drives for new build.

July 30, 2013 | 11:06 PM - Posted by irdmoose

Hey Allyn, thanks for the great review. It looks like the bug you caught to get this review out may have been worth it, and I hope that you get well soon! How well do you think these drives will perform in a RAID-0 setup with say an Intel controller on either Ivybridge or Haswell systems?

August 12, 2013 | 12:50 AM - Posted by Allyn Malventano

They should be just fine, so long as the partition is correctly aligned (not an issue for Vista and newer). There may be a slight performance hit due to TRIM not passing through to a RAID-0 (which is still a mixed bag as far as it actually working), but it should be minimal impact for regular usage.

August 13, 2013 | 03:08 PM - Posted by jgstew

I think in the case of workloads with very little writing like a file server, the 840 EVO and similar SSDs could be an interesting replacement for something like this:

With a significantly lower $/GB and better read performance.

August 23, 2013 | 05:38 PM - Posted by klatch

Is there a concern that the flash in the turbowrite buffer is going to die early? or does it get load balanced around the drive? I was sort of expecting the buffer to actually be SLC, but if it is just making TLC operate as SLC is that functionally equivalent to it being SLC?

September 17, 2014 | 10:45 PM - Posted by Grand Nagus (not verified)

Allyn Malventano

What is the update on the 840 EVO problems?


If they don't fix the problem you should downgrade the review to Bronze or worse. :)

I bought this drive on PCPERs recommendation and now I'm pissed.

December 25, 2014 | 10:54 PM - Posted by Obat Kanker Vulva Herbal (not verified)

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