Endurance

Samsung isn't quoting any specific TB written values for how long it expects the EVO to last, although the drive comes with a 3 year warranty. Samsung doesn't explicitly expose total NAND writes in its SMART details but we do get a wear level indicator (SMART attribute 177). The wear level indicator starts at 100 and decreases linearly down to 1 from what I can tell. At 1 the drive will have exceeded all of its rated p/e cycles, but in reality the drive's total endurance can significantly exceed that value.

Kristian calculated around 1000 p/e cycles using the wear level indicator on his 840 sample last year or roughly 242TB of writes, but we've seen reports of much more than that (e.g. this XtremeSystems user who saw around 432TB of writes to a 120GB SSD 840 before it died). I used Kristian's method of mapping sequential writes to the wear level indicator to determine the rated number of p/e cycles on my 120GB EVO sample:

Samsung SSD 840 EVO Endurance Estimation
  Samsung SSD EVO 120GB
Total Sequential Writes 4338.98 GiB
Wear Level Counter Decrease -3 (raw value = 35)
Estimated Total Writes 144632.81 GiB
Estimated Rated P/E Cycles 1129 cycles

Using the 1129 cycle estimate (which is an improvement compared to last year's 840 sample), I put together the table below to put any fears of endurance to rest. I even upped the total NAND writes per day to 50 GiB just to be a bit more aggressive than the typically quoted 10 - 30 GiB for consumer workloads:

Samsung SSD 840 EVO TurboWrite Buffer Size vs. Capacity
  120GB 250GB 500GB 750GB 1TB
NAND Capacity 128 GiB 256 GiB 512 GiB 768 GiB 1024 GiB
NAND Writes per Day 50 GiB 50 GiB 50 GiB 50 GiB 50 GiB
Days per P/E Cycle 2.56 5.12 10.24 15.36 20.48
Estimated P/E Cycles 1129 1129 1129 1129 1129
Estimated Lifespan in Days 2890 5780 11560 17341 23121
Estimated Lifespan in Years 7.91 15.83 31.67 47.51 63.34
Estimated Lifespan @ 100 GiB of Writes per Day 3.95 7.91 15.83 23.75 31.67

Endurance scales linearly with NAND capacity, and the worst case scenario at 50 GiB of writes per day is just under 8 years of constant write endurance. Keep in mind that this is assuming a write amplification of 1, if you're doing 50 GiB of 4KB random writes you'll blow through this a lot sooner. For a client system however you're probably looking at something much lower than 50 GiB per day of total writes to NAND, random IO included.

I also threw in a line of lifespan estimates at 100 GiB of writes per day. It's only in this configuration that we see the 120GB drive drop below 4 years of endurance, again based on a conservative p/e estimate. Even with 100 GiB of NAND writes per day, once you get beyond the 250GB EVO we're back into absolutely ridiculous endurance estimates.

Keep in mind that all of this is based on 1129 p/e cycles, which is likely less than half of what the practical p/e cycle limit on Samsung's 19nm TLC NAND. To go ahead and double those numbers and then you're probably looking at reality. Endurance isn't a concern for client systems using the 840 EVO.

Inside the Drives & Spare Area TurboWrite: MLC Performance on a TLC Drive
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  • abhilashjain30 - Wednesday, October 02, 2013 - link

    Samsung Evo Series now available online in India. You can check on OnlySSD dot com or PrimeABGB dot com Reply
  • MVR - Thursday, November 14, 2013 - link

    It will be very interesting when they start loading these up with more than 512MB of DRAM cache. Imagine a drive with 4-8+ GB on board. The response times would be insane. It is only a matter of time considering you can buy 8GB of SODIMM memory for $70. They could probably put it on board for $50 added cost to the drive - then these would truly act like PCIe SSD cards, except it would totally max out the SATA3 throughput limit. Reply
  • MVR - Thursday, November 14, 2013 - link

    Of course SATA revision 3.2 at 16gbit/sec would sure enjoy it. Imagine a pair of those in RAID 0 :) Reply
  • Wao - Sunday, November 24, 2013 - link

    I'm going to change my old noisy hard disk with a Samsung 840 EVO 1TB model. I am wondering if I really need to enable TRIM in OS X. I check the data sheet. It only said "Yes" about garbage collection and TRIM support. Does it meant that this model has its own garbage collection built-in, or I really need to enable TRIM in OS X. Honestly, I don't like to hack around the system files.
    Thanks !
    Reply
  • iradel - Monday, November 25, 2013 - link

    In the "IMFT vs. Samsung NAND Comparison" table, how did you get a Pages per Block value of 256 for 19nm TLC (a.k.a. the 840 EVO)? 8KB * 256 pages per block would imply an erase block size of 2048KB, whereas I've read that the 840 EVO has an EBS of 1536KB (which would mean 192 pages per block).

    Where did you get the 256 value?
    Reply
  • Scraps - Tuesday, November 26, 2013 - link

    What would be the optimum configuration for this situation. A MacBook Pro with 2 samsung evo 1tb. Would striped raid zero be the best ? Reply
  • code42 - Wednesday, December 18, 2013 - link

    Can I use the Samsung 840 Pro 1TB with a NAS solution? Can some propose a nice setup? Thanks Reply
  • Hal9009 - Wednesday, December 18, 2013 - link

    Just received my new ASUS N550JV and updated the slow HD with 840 EVO-Series 750GB SSD, 16GB of G.SKILL 16GB (2 x 8G) 204-Pin DDR3 and a fresh copy of win-7x64...could not be happier, Samsung makes great SSDs Reply
  • 7beauties - Saturday, December 28, 2013 - link

    I bought the Samsung 840 EVO 1TB because Maximum PC gave it a 9 Kick *ss award, but they described it as being MLC. Good ole Anand tells it like it is. This is TLC. I was pretty steamed with Samsung because they describe this as their "new 3 bit MLC NAND," which I wouldn't have bought over Crucial's M500 960GB MLC SSD. Though Anand tries to calm fears of TLC's endurance, I can't understand what a "GiB" is and how I can calculate my drive's life span. Reply
  • verjic - Thursday, February 13, 2014 - link

    I have a question. In some of the tests I found of real life use shows that Kingston V300 and Samsung a practically the same speed and even at copy 2 GB of 26000 files is slowly on samsung with about 30 %!!! Also installing a program like photoshop, takes longer on Samsung than Kingston, difference is not so big but is arou 10-15 %. Why is that? From all the test for kingston and Samsung, everyone say that Samsung is better but I don't see how? If anyone can explain to me, please Reply

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