Samsung SSD 840 EVO Review: 120GB, 250GB, 500GB, 750GB & 1TB Models Tested
by Anand Lal Shimpi on July 25, 2013 1:53 PM EST- Posted in
- Storage
- SSDs
- Samsung
- TLC
- Samsung SSD 840
Inside the Drives & Spare Area
The EVO is offered in a single form factor - 2.5" at a 7mm thickness. There are three torx (T5) screws that hold the chassis together, removing them gets you a look at the EVO's very simple internals. Surprisingly enough there's no thermal pad between Samsung's MEX controller and the chassis.
Samsung, like Intel, does a great job of reducing the number of screws and simplifying the assembly of its drives. I would prefer if Samsung didn't insist on using torx screws to hold the chassis together but I'm sure it does have some impact on reducing returns. There's also growing concern of counterfit SSDs which I guess screw choice could somewhat address.
There are two PCB sizes used in the EVO lineup, neither of which occupies the full volume of the 2.5"/7mm chassis. The 120 and 250GB drives use the smallest PCB, while the other drives use the larger layout. The larger PCB has room for 8 NAND packages, while the half length PCB can accommodate two. Each of the NAND packages can hold up to 8 x 128Gbit 19nm TLC die.
To deal with the realities of TLC, Samsung sets aside more of the drive for use as spare area on the EVO than it does on its MLC Pro line. Due to TurboWrite however, the percentage is actually a bit less than it was on last year's 840.
| Samsung SSD 840 EVO Memory | |||||||
| Advertised Capacity | 120GB | 250GB | 500GB | 750GB | 1TB | ||
| DRAM Size | 256MB LPDDR2-1066 | 512MB LPDDR2-1066 | 512MB LPDDR2-1066 | 1GB LPDDR2-1066 | 1GB LPDDR2-1066 | ||
| # of NAND Packages | 2 | 2 | 4 | 8 | 8 | ||
| # of NAND die per Package | 4 | 8 | 8 | 4 | 8 | ||
| NAND Capacity per Package | 64 GiB | 128 GiB | 128 GiB | 96 GiB | 128 GiB | ||
| Total NAND | 128 GiB | 256 GiB | 512 GiB | 768 GiB | 1024 GiB | ||
| Spare Area | 12.7% | 9.05% | 9.05% | 9.05% | 9.05% | ||
I've tossed internal shots of all of the EVO lineup into the gallery below:
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verjic - Thursday, February 13, 2014 - link
I'm talking about 120 Gb versionverjic - Thursday, February 13, 2014 - link
Also what is Write/Read IOMeter Bootup and Write/Read IOMeter IOMix - what means their speed? Thank YouAhDah - Thursday, May 15, 2014 - link
The TRIM validation graph shows a tremendous performance drop after a few gigs of writes, even after TRIM pass, the write speed is only 150MBps.Does this mean once the drive is 75%-85% filled up, the write speed will always be slow?
I'm tempted to get Crucial M550 because of this down fall.
njwhite2 - Wednesday, October 15, 2014 - link
Kudos to Anand Lal Shimpi! This is one of the finest reviews I have ever read! No jargon. No unexplained acronyms. Quantitative testing of compared items instead of reviewer bias. Explanation of why the measured criteria are imortant to the end user! Just fabulous! I read dozens of reviews each week, so I'm surprised I had not stumbled upon Anandtech before. I'm (for sure) going to check out their smartphone reviews. Most of those on other sites are written by Apple fans or Android fans and really don't tell the potential purchaser what they need to know to make the best choice for them.IT_Architect - Thursday, October 22, 2015 - link
I would be interested in how reliable they are. The reason I ask is one time, when the time the Intel SLC technology was just under two years old, and there was no MLC or TLC, I needed speed to load a database from scratch 6 times an hour during incredible traffic times. I was getting requests by users at the rate of 66 times a second per server, which each required many reads of the database per request. I couldn't swap databases without breaking sessions, and mirror and unmirror did not work well. I would have to pay a ton to duplicate a redundant array in SSDs. Then I asked the data center how many of these drives they had out there. They (SoftLayer) queried and came back with 700+. Then I asked them how many they've had go bad. They queried their records and it was none, not so much as a DOA. I reasoned from that I would be just as likely to have a chassis or disk controller go bad. None of them have any moving parts, and the drives are low power. Those were enterprise drives of course because that's all there was at that time.In 2011 I bought a Dell M6600. Dell was shipping them with the Micron SSD. I was concerned about the lifespan and I do a lot of reading and writing with it and work constantly with virtual machines while prototyping, and VM files are huge. It calculated out to 4 years. While researching, I came across that situation where Dell had "cold feet" about OEMing them due to lifespan. Micron/Intel demonstrated to them 10x the rated lifespan, which convinced Dell. There was plenty of other trouble with consumer-level SSDs at the time, which gave the technology a bad name. The Micron/Intel was one of the very few solid citizens at the time. I went with it, although I didn't buy my M6600 with it because Dell had such a premium on them. I had two problems with the drive, which by the way is still in service today. The first was the drive just stopped doing anything one day. I called Micron and it turned out to be a bug in the firmware. If I had two drives arrayed, it would have stopped both at the same time. I upgraded the firmware and never had that problem again. The next time I was troubleshooting the laptop and putting the battery in and out and the computer would no longer boot. I again called Micron. It was by design. They said disconnect the power, pull the battery, and wait one hour. I did, and it has worked perfectly since. If I had an array, it would have stopped both at the same time.
Today, the market is much more mature and the technology no longer has a bad name. A redundant array is no substitute for a backup anyway. A redundant array brings business continuity and speed. Are we just as likely or more so to have a motherboard go out? We don't have redundant motherboards unless without having another entire computer. Unlike a power supplies and CPUs, SSDs are low-current devices. I'm considering the possibility that we may be at the point, even for consumer-level drives, where redundant arrays for SSDs are just plain silly.
Gothmoth - Sunday, January 8, 2017 - link
in real life my RAPID test showed no benefits AT ALL!!all it does is making low level benchmarks look better.
you should test with real applications. RAPID is a useless feature.
jeyjey - Friday, June 7, 2019 - link
I have one of this drive. I need to find a little part that is fired, I need to replace it to try to enter the data inside. Please help.