Samsung 840 EVO SSD Review – Samsung Caches In On Value and Performance


Turbowrite is brand new to the Samsung EVO SSD and is a caching mechanism that increases the performance of the EVO immediately and has a measurable result.  Where last gen’s 840 120GB SSD was only capable of 130MB/s high sequential write data transfer speed, the 840 EVO triples that to 410MB/s.  This is the direct result of Samsung TurboWrite and this performance has never been seen prior except where compression was used in the drives storage.  The performance upgrade between the 840 and 840 EVO is evident in the specifications and comparison chart shown here:

Samsung 840 EVO vs 840 Performance Comparison

Performance of the 840 EVO is variable and dependent on capacity.  Those seeking smaller capacity SSDs will be very surprised at the speeds Samsung has squeezed out of their 120 and 250GB SSDs through implementation of TurboWrite Technology, the performance improvement documented in product specs. While read performance remains consistent, the 840 EVO 120GB SSD has more than 3x the write performance of the same capacity of last generation (410/130) while the 250GB is a bit less with a 2x performance jump (520/250).


TurboWrite is a product of Samsung’s firmware where a small portion of each SSDs memory is used as simulated SLC NAND flash memory.  During data transfer, a high performance write buffer is created by TurboWrite where write data is held within the buffer, completing its trip to the memory when idle time occurs in the drive.  This increases the speed of data transfer significantly.  The size of the TurboWrite buffer varies depending on capacity of the solid state drive and the various buffer sizes can be seen in this slide from the Global Summit:


The size of the buffer is key to data transfer and should the buffer become full or should a file require storage that is larger than the buffer size, that data will be stored outside the buffer and in real time at a slower level than that in the buffer.  Once the buffer is cleared, write performance will resume at the higher speeds.  This chart displays the speed of data transfer while TurboWrite is in play and while it is not:

TurboWrite Speeds before and after

Probably the biggest takeaway with TurboWrite is that its effect is immediate, can be measured and is noticeable.  Technically, Samsung didn’t even have to speak of TurboWrite and the consumer would have simply believed that Samsung has upped the ante with their low capacity drives.  From our perspective, this is refreshing as too many times in the past companies have introduced this or that caching solution where the results couldn’t be immediately observed or were simply some small boot time increase.

 Samsung EVO 840 1TB SSD Featured 1


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    super fast review – love ie

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    Great review Les. This drive is probably the most exciting development in the consumer SSD space to date. We can’t wait to get our hands on these down under in Australia.

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    Seems like a great SATA3 drive. However, I can’t help but feel like it’s a “bridge” drive. I mean, NGFF m.2 drives with direct PCIe connection are starting to appear, and they should have over 1GB/s read/write without any RAPID technology involved. This drive is for current systems that use a SATA port (99.999% of the market), but direct PCIe connection is the better way to go.

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      Wow….this could be a long response. You are absolutely right when you say that PCIe will be the future. It will take a few years, if not longer to completely implement, however, and manufacturers have already stated that it will have OEM, and not, retail availability initially. This makes great sense as there just isn’t the need for PCIe just yet.

      Samsung is striking at the present and want to get those that are yet to migrate, which is the majority of the population. The biggest obstacle with SSD transition has always been lack of knowledge and then fear of difficulty in migration. I feel Samsung has hit this head on and made this the most attractive opportunity for the consumer today. Considering that SSDs are still in their infancy, that’s a very big market.

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        Agreed. However, for those of us regularly visiting this site, I think we are mostly looking for the latest and the greatest, which the EVO certainly represents, except for the SATA III bottleneck. Just like with 4G LTE data speeds being discussed in terms of “fast enough for most people”, and the same being the case as far as prowess of CPUs are concerned, we still want PCIe now instead of later. Mid-2013 MacBook Air owners are already there with Samsung again leading the way. Of course, there is also the issue of where would we plug in a PCIe SSD in a small form-factor computer.

        I also have a separate question on the EVO being sold as a “consumer drive”, mostly being compared to only the 840, instead of the 840 Pro, at least in addition to the 840. Does this mean that some kind “EVO Pro” version is in the offing? If you know, that is. I don’t remember reading about such a drive or any leads from Samsung?

        Thanks again! 🙂

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        There will be no 840 Evo Pro, but rather a future release of Samsung Magician with RAPID for the present Samsung Pro. Samsung is very happy with where they are at with the 840 Pro.

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        OK, so the 840 EVO replaces the 840 and then there’s the 840 Pro that remains, is that about right? Thanks so much for quick responses, Les. I need to choose a new SSD to buy either today or tomorrow, so I guess I can still buy the 840 Pro and get (most? all?) of the benefits of the EVO just with a software update?

        Thanks again, you rule! (but you knew that… ;-P)

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        Will the Samsung Magician update for the 840 Pro ALSO help the 840 ?

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        You will have to clarify this a bit more.

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    Great and timely coverage. Thanks!

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    Am I the only one who believes that all SSDs (enterprise, prosumer and consumer) should have the supercaps installed?? The threat of data loss caused by a power interruption is rather nasty regardless of the users classification. I had hoped the EVOs would address this once and for all. With onboard memory caches getting larger and larger the potential for substantial data loss/corruption grows as well. It’s time for vendors to stop using supercaps as a marketing gimmick.

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    Wow! This thing comes so close to the Pro and actually surpasses it in some tests!
    The 4k reads are better and access times are on par!
    Can’t help but think that at that price it will Dominate!
    Rapid is great too. I mean who runs a high end system without UPS anyway…
    I can’t wait to see 840Pro performance with rapid though!

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      Yes, UPS would be a nice standard addition to consumer SSDs as we are starting to see it trickle down. Personally, I believe there is a demographic that will look for power loss protection as a requisite to their purchase.

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      A UPS will only protect you if the AC power fails. If you blow the power supply or mobo your SSDs data is toast without the supercaps.

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        Exactly! But it’s just a button!
        Can’t you turn it off when testing out your OC settings?
        And if you don’t OC then what, can’t you just verify your systems stability with some bench tools?
        After all if you fry your mobo, who cares about the windows installation? I don’t think you Store your family fotos on an ssd.
        To me it’s just common sense. FREE performance!

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    OK, so who would get the 840 Pro over an 840 EVO at this price point? You mentioned that the Pro is not going away and is “suited” for certain applications? (as in better than the EVO?)

    Also, as far as this new RAPID technology is concerned, why is it not an always-ON feature? Why would anyone turn it off other than maybe for what, power savings reasons or wear and tear? Do we have availability now or soon?

    Thanks for a great review of what looks to become my next SSD and SOOON!!! 😀

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      Availability is expected within the next two weeks. RAPID is an always on feature and I spoke to that in the article. As for whether I would get one or another…. I really like RAPID. If it was an immediate necessity, I might grab the 840 EVO for that and the capacity. If I was to wait, I might go with the pro with the new version of Samsung Magician when it comes out but there is not a definite date on that, hence we dont know when RAPID will be available for the 840 Pro.

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        I see. Thank you for that!

        Alright, so let me please ask you to clarify that as the SOFTware will be compatible with the 840 Pro – perhaps for the sake of features such as manual provisioning – this software does NOT have ANY effect on the speediness of the 840 Pro as far as certain HARDware components are concerned, is that right? And those being certain features and technologies, which the software can only enable in “next-gen” 840 EVO SSD’s, because only the EVO supports it/them?

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        Current Magician software allows manual over provisioning and only the next for the Pro (TBA) will allow RAPID.

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    I noticed that most of your benchmarks show the write speed while it’s in burst mode. For longer sequential writes (maybe after 5-10seconds), it seems like the data rate drops a LOT (from 450->320 or so).

    Given that, if you could get the Plextor M5P (256gb) on sale for $190 like it was recently, which would be a better purchase? I believe the Samsung 840 EVO 256gb would be slightly faster in reads, about the same speed for small writes, but considerably (35% slower) in long sequential writes.

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    So, first I want to say thanks reading your reviews have helped me out with choosing a hard drive. I have a question do you know if it is a definite that Samsung is going to release RAPID for the 840 Pro software?

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      Yes this is an absolute which will be seen in a future release of Samsung Magician and this Fall.

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        I actually never got a chance to see this until after I already put my Samsung pro in rapid mode, and it definitely an awesome feature. I am having a hard time knowing what data to transfer to my mechanical drive from the SSD boot drive, because I do not know what will affected if I do. I have like 10 gb on a 256 boot drive and you can definitely see the difference in speed from when it has more free space on there. Especially with loading windows which everything would be in a rush to load up for first place before. Now it is more inconsistent, but I believe I will just look up on google about how to safely and efficiently transfer the data.

        Oh and btw thanks a lot for the reply about the release date of Rapid to the 840 pro. It was still appreciated none the less even if I never saw the reply until now.

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        I am glad you got everything set up properly. Enjoy!

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    Strange, the new magician software v4.2 includes the new rapid mode but my Samsung 840 pro ssd is shown as not a supported ssd. Will it be supported in the future?

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    Hi Les, just curious – in terms of real world performance – would you go for a SanDisk extreme 2 or a Samsung Evo 250gb? These are the 2 i’m looking at. Based on the specs the Evo wins hands down but is this the case for real world performance? Is everything “lightning fast” in loading and booting?

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    Am pleased to hear this; because I have just finished building my i7 4770 Sabertooth Z87 PC and This SSD running Test Windows 8.1 and the Samsung Magician software told me the SSD RAPID MODE is not supported, which seemed odd as this is the Samsung software for the SSD.
    Patience is a virtue which brings rewards.
    I hope 20% of 128 GB is enough Over-provisioning.

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    Les, I’ve noticed a lack of reporting on any “real world” experiences with RAPID mode turned on. Benchmarks seem amazing with RAPID, but can any of that be felt in real world use? Or does the feature blur the line even further between what’s seen on benchmarks and what’s experienced? Ie. making something really fast, faster, will still be really fast.

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    Hey Les, I’m looking to build a RAID 0 out of 2 drives to write WAV files to via a DAW such as Pro Tools, Ableton, etc. Would you recommend the 840 Pro or 840 Evo for such a setup? Thanks.

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    Hi! Sombody knows if its really compatible with SATA 1?
    In Samsung´s manual say its is, but in the box says its only compatible with SATA 2. Somebody really use this disk in SATA 1?
    PD: Sorry for my English!!!!

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