Review Index:

Samsung 840 Pro 512GB SSD Full Review - Samsung Ups the Ante

Subject: Storage
Tagged: 840, mdx, pro, Samsung, ssd

Introduction, Specifications and Packaging


Samsung has been at this SSD thing for quite some time now. The first SSD I bought was in fact a Samsung unit meant for an ultraportable laptop. Getting it into my desktop was a hack and a half, involving a ZIF to IDE adapter, which then passed through yet another adapter to convert to SATA. The drive was wicked fast at the time, and while it handily slaughtered my RAID-0 pair of 74GB VelociRaptors in random reads, any writes caused serious stuttering of the drive, and therefore the entire OS. I was clearly using the drive outside of its intended use, but hey, I was an early adopter.

Several SSDs later came the Intel X25-M. It was a great drive, but in its earliest form was not without fault. Luckily, these kinks were worked out industry-wide, and everyone quickly accelerated their firmware optimizations as to better handle random writes. Samsung took a few generations to get this under control. The first to truly get over this hump was the 830 Series, which launched earlier this year. It utilized a triple core Arm 9 CPU which was able to effectively brute force heavy random write workloads. It also significantly increased the speed and nimbleness of the 830 across the board, which combined with Samsung's excellent reliability record, quickly made it my most recommended series as of late.

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...and now we have the 840 Series, which launched today. Well, technically it launched yesterday if you're reading from the USA. Here in Korea the launch started at 10 AM and spanned a day of product press briefings leading to the product NDA expiration at 8 PM Korea time. This review will focus on the 512GB capacity of the 840 Pro model. We will follow on with the 840 (non-pro) at a later date:

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Read on for the full review!


  • Capacity:              64GB, 128GB, 256GB, 512GB
  • Sequential Read:   540MB/sec
  • Sequential Write:   450MB/sec
  • Random Read:      100,000 IOPS
  • Random Write:      87,000 IOPS
  • Active Power Use: 0.068W (down from 0.24W for 830 Series)
  • Idle Power Use:     0.042W (down from 0.14W for 830 Series)


As we received an advance sample of the 840 Pro, sans packaging. Whie I couldn't do my typical open-packaging photo, I was able to snag this at the Summit. This shows both the 840 (non-pro) and the 840 Pro:

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Video News

September 24, 2012 | 07:05 AM - Posted by najirion

Wow! Everything is getting more energy efficient nowadays. Good job Samsung!

September 24, 2012 | 09:44 AM - Posted by Mark (not verified)

I just picked up a 830 120g for $97 on Newegg, I didnt even need it but I had to considering the good deal (impulse buy), makes sense considering this release, Samsungs on top!.

September 24, 2012 | 10:08 AM - Posted by GettinThere (not verified)

Got the 830 and I don't think I would know the difference with an 840- but I'm glad the tech is getting better.

Now if they can just get the price down ....

Go competition!

September 24, 2012 | 10:15 AM - Posted by tbone (not verified)

i really dont see a reason to get the 840 pro yet

the 840pro/830 seems to be trade blows, with the 830 coming out ahead in more tests.

am i missing something?

September 24, 2012 | 10:31 AM - Posted by Anonymous (not verified)

My Samsung 830 has been the most reliable SSD over the years.

I'm sticking with Samsung in this department.

September 24, 2012 | 12:00 PM - Posted by very interesting (not verified)

Any reason to upgrade from my Intel X-25M 160GB?
Core i7 2600K OC 16GB ram main desktop

September 24, 2012 | 02:11 PM - Posted by Anonymous Coward (not verified)

Seems to me like the 840 fails to consistently beat the 830 or the intel 520 in some of your tests. It's not clearly better across the board, and when it does win it looks like a modest incremental improvement.

I don't know if it's the controller, or what, but it seems to me like the next leap in SSD performance will come only with a controller change. Samsung and Intel seem to have squeezed out every drop out of the Sandforce controller.

Nonetheless Allyn, thanks for your review. I wouldn't buy or recommend an SSD these days without reading your reviews. There's something about the SSD market that makes reviewers act like fanboys, and even otherwise serious review sites are filled with low-depth OMG IT'S FAST OH WOW reviews that don't get to more in depth testing, including reliability testing and speed degradation, RAID behavior, type and frequency of firmware updates, etc.

September 24, 2012 | 03:08 PM - Posted by Mark (not verified)

840 Pro is an evolutionary upgrade with 21nm 2bpc MLC NAND. The regular 840 is said to have the performance inline with the 830

September 24, 2012 | 07:34 PM - Posted by tbone (not verified)

i now see the reason to upgrade to the 840 over the 830

power consumption is nice!

September 25, 2012 | 08:16 AM - Posted by Allyn Malventano

Unfortunately there was no time to get this data prior to the flight out to the press event. I will be measuring power consumption on both the 840 Pro and the standard 840 upon my return.

September 25, 2012 | 06:47 PM - Posted by Anonymous Coward (not verified)

You care about power consumption in your SSD? Really? Talk about stepping over dollars to pick up pennies! If you have enough wiggle room in your budget to pick something based on power usage, there are a lot more bang for the buck areas than an SSD that uses (and dissipates) enough power that it can be cooled by a passive plastic housing. You sir, are a moron.

November 15, 2012 | 09:59 PM - Posted by Anonymous (not verified)

Apparently you've never heard of "laptops" or "battery life".

September 24, 2012 | 09:34 PM - Posted by Anonymous (not verified)

Why don't you try testing the drives with data on them and see how they really perform.

September 25, 2012 | 08:12 AM - Posted by Allyn Malventano

Every drive we test is properly preconditioned prior to any benchmarks run. 

September 27, 2012 | 01:16 PM - Posted by Dano (not verified)

it's tough to do a test like that and get accurate results. each drive would have to have the exact same amount of data on it in order to rule out any variables, which alone is difficult, but also some of the disks tested are different sizes and would be impossible to get a good comparison of the drives.

September 28, 2012 | 06:01 PM - Posted by Anonymous (not verified)

So, where do I buy one of these?

September 29, 2012 | 10:46 AM - Posted by Anonymous (not verified)

Isn't tlc supposed to have only 1/4 of the writing endurance of current mlc? At least according to that article

Going from 3k writing cycle to 0.75k looks like huge dip rather than a "minor" dip in endurance like you said in your conclusion.
I can already imagine people not aware of this aspect bashing those sdd for unreliability once they discover that their sdd is almost dead after a period of heavy use.

October 1, 2012 | 06:19 PM - Posted by Anonymous (not verified)

Good review of drive performance. I'd like to see you include a review of the endurance spec and actual measure if possible. Further would like to see what the impact is running these tests when the drive is already > 80% full.

Tom Stephenson

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October 16, 2012 | 05:50 AM - Posted by Hans Maier (not verified)

Looks like the SAMSUNG 840 now catches up with the INTEL 540.
Main reason for SAMSUNG seems to be the power consumption and reliabilty and Price/GB ratio. But all this isn't really tested or documented here. I've seen the 840 Pro already for much lower prices (but now it's a month ago that this article was written).

Could you please add the following points:
- performance when disk is 80-90% full
- power consumption
- raid behavior ?

Thanks in advance!

December 2, 2012 | 01:23 AM - Posted by Steeda1974 (not verified)

Its funny that people pick at the the lower power consumption. I bought a neutron gtx 240gb and have now replaced it with a 840 pro 256gb all b/c of power consumption. I cant tell a difference in real world activities but I am so glad i spend the extra money for the drive b/c it lasts 30 minutes longer or more on average. Given it comes with a 5 year warranty over standard 3 year warranties and my laptop lasts 30 minutes longer before i plug it in, I think $80-100 extra for the convenience and reliability with a 5 year warranty is well worth it when you can use the drive over a 5 year period. That will mean a lot to people with laptops. It even beat my agility 2 drive and that used a lot less power too.

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