Performance Consistency

Performance consistency tells us a lot about the architecture of these SSDs and how they handle internal fragmentation. The reason we do not have consistent IO latency with SSDs is because inevitably all controllers have to do some amount of defragmentation or garbage collection in order to continue operating at high speeds. When and how an SSD decides to run its defrag or cleanup routines directly impacts the user experience as inconsistent performance results in application slowdowns.

To test IO consistency, we fill a secure erased SSD with sequential data to ensure that all user accessible LBAs (Logical Block Addresses) have data associated with them. Next we kick off a 4KB random write workload across all LBAs at a queue depth of 32 using incompressible data. The test is run for just over half an hour and we record instantaneous IOPS every second.

We are also testing drives with added over-provisioning by limiting the LBA range. This gives us a look into the drive’s behavior with varying levels of empty space, which is frankly a more realistic approach for client workloads.

Each of the three graphs has its own purpose. The first one is of the whole duration of the test in log scale. The second and third one zoom into the beginning of steady-state operation (t=1400s) but on different scales: the second one uses log scale for easy comparison whereas the third one uses linear scale for better visualization of differences between drives. Click the dropdown selections below each graph to switch the source data.

For more detailed description of the test and why performance consistency matters, read our original Intel SSD DC S3700 article.

Samsung SSD 850 EVO 250GB
25% Over-Provisioning

The 850 EVO presents a healthy increase in IO consistency. The 840 EVO wasn't exactly inconsistent in the first place, but the 850 EVO takes the steady-state IOPS from ~3,000-5,000 IOPS to 5,000-8,000 IOPS, which is actually nearly on par with the 850 Pro. The 850 EVO has without a doubt one of the highest performance consistencies out of the value/mainstream drives we have tested.

Samsung SSD 850 EVO 250GB
25% Over-Provisioning


Samsung SSD 850 EVO 250GB
25% Over-Provisioning

TRIM Validation

To test TRIM, I filled a 120GB 850 EVO with sequential 128KB data and proceeded with a 30-minute random 4KB write (QD32) workload to put the drive into steady-state. After that I TRIM'ed the drive by issuing a quick format in Windows and ran HD Tach to produce the graph below.

And TRIM works as expected.

Endurance: Close to Planar MLC NAND AnandTech Storage Bench 2013


View All Comments

  • sylerner - Thursday, August 13, 2015 - link

    The over-provisioning figures in the article are larger than the actual over-provisioning values.

    The source of error is failure to account for the flash memory used for TurboWrite.

    The correct values are:
    120GB: 10.6%
    250GB, 500GB and 1TB: 8.0%
  • Lonerski - Sunday, January 31, 2016 - link

    Did you use Rapid Mode in those benches ? Reply
  • CricDasher - Thursday, March 3, 2016 - link

    Samsung SSD 850 Evo is a life-changer for anyone who uses it. With the sleek and beautiful build quality, Evo 850 does obviously come with a great price tag.

    There are of course different capacities of the given product, but I preferred to use the 120 GB version, largely due to the relatively low price and my actual need of owning an SSD.

    My major requirement was to install the Operating System and few other mostly used applications inside the SSD, so that the whole computer looks so fast. Samsung Evo 850 120 GB SSD has done the job fantastically for me so far and I highly recommend this product to everyone.

    Out of the sellers online, GearBest seems to offer the best package since GB is a trusted source of products. They are offering a flash sale at the moment and you may try it to get it for a relatively a low price.
  • Budburnicus - Friday, March 11, 2016 - link

    Samsung OWNS the SSD market! When I can buy an 850 EVO 500 GB model for just $110 and get for all intents and purposes, the BEST possible speed from a SATA 6 drive - there is REALLY NO POINT in buying ANY other brand!

    I mean the 850 EVO keeps up with, and sometimes even SURPASSES the 850 PRO - often in ways that will benefit the average power user/gamer more!

    I wonder how much of that is due to the 6 GB of SLC write cache - as the 850 PRO series has no SLC NAND whatsoever!

    Also, once the "Magical" storage capacity of 480 GB and above is reached, again, for JUST $110 - not only is that more than sufficient to hold my OS and all the games I play, but all SSDs tend to perform best at 480 GB and above, I would say for the 850 EVO series, this is DOUBLY TRUE! Due to the fact that the 500 GB model has a full 6 GB of SLC Turbo-write NAND (compared to 3 for the 250 and 120) - but it also has a full 512 MB of DDR3L on it!

    I dunno why Anandtech has it listed as DDR2L memory, but it is indeed DDR3L RAM on ALL Samsung 850 series drives!
  • Tornadotuan - Friday, July 8, 2016 - link

    Hi Hardware Community,
    I know this article is quite outdated right now, nevertheless the actual topic of the authors "Final Words" bug me right now. Especially now that enough time for longtime-endurance tests has passed.

    Anyway, I can´t choose between the Samsung EVO 850 1TB v2 (289€) and die SanDisk Extreme 960GB (281€).
    So pricewise the "Pro" is even cheaper right now compared to the Samsung. But there are some obvious differences:

    - TLC 3D V-NAND vs. MLC Planar
    - 5 years vs. 10 years warranty
    - 150 TBW vs. 80 TBW
    - higher Peak vs. consistency
    - Samsung Bugging vs. sudden death drives

    My usage:
    - Client for everything: gaming, programming, office, multimedia - averything
    - gonna split it in system and data-partition
    - gonne be in laptop that´s used as desktop
    - battery is wasted, so no concern about power consumption

    So, usually I use hardware until it´s broken so meaning about 8-10 years.
    Still I want steady performance without sudden decline in speed like with the EVO 840 :C
    I´d be really glad, if you could tell me your opinion on this :)
  • Robbin1111 - Saturday, April 28, 2018 - link

    Awesome drivers! Anyone has a code for this? I checked several sites, like,

    but couldn't find one. My mom has an aging Dell D830, which is very slow and I'm looking for a reasonably priced replacement, and I think this driver is great.
  • rocky12345 - Thursday, January 30, 2020 - link

    Yes this is a older review but just posting in 2020 on how my Samsung 850 EVO 500Gb has stood up to the wear & tear of every day computing. I have had my drive since 2015 in a computer that is on for many hours a day since I got the drive.

    The system gets used a lot so everything gets a really nice work out everyday. According to the Samsung software my drive is only at 2% of it's rated endurance lifespan. Not to bad for a drive that gets hit pretty hard everyday with reads and writes and to still have 98% life endurance left after all these years of use.

    I read this review back in 2014 and it was one of the reasons I decided to get this drive for my system. I just came from a new write up form this site talking about a Midrive setup. What got me thinking about TLC nand was not the write up itself but a comment from a user and how they were saying just how bad QLC & TLC nand was and how they had low endurance lifespans.

    Am I missing something here? My drive has TLC 3D V-nand made by Samsung and the drive is still at 98% endurance left on the SSD. Is Samsung's 3D V-nand better than regular TLC chips and lasts longer because of it. Yes my drive is getting up there in age and I plan on replacing it once I do a full system update and I will be getting a much faster NVMe PCI-e 4.0 drive.

    As for the Samsung SSD I probably will use it to cache my 4 4TB hard drives since AMD has that caching setup in their platform and I can still find a good use for the Sata SSD I currently have. For now it is very snappy and the system feels very fast still with things such as Chrome or Firefox opening in half a second or Windows still booting up in a mere 7 seconds right after the bios post screen to the desktop so not worried about speed just quite yet.

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