Customer Reviews: Samsung MZ-7TD250BW 840 Series Solid State Drive (SSD) 250 GB Sata 2.5-Inch
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on November 6, 2012
First of all, the Samsung 840 uses triple-level cell (TLC) memory vs. the multi-level cell (MLC) memory used for almost all other SSDs. So what is the difference between TLC and MLC? With TLC memory, 3 bits of information (8 possible values) are stored per cell instead of the 2 bits (4 possible values) in MLC memory. This might sound better but it also means that the cells are used more and there is less voltage fault tolerance. In the most simple terms, you can think of cells being "filled" or "emptied" by applying voltage. When 3 bits (8 possible values) of information are stored per cell, the SSD may have to apply voltage to the entire cell multiple times even though just one bit of information is encoded (depending on the bit being changed). The multiple voltage applications to each cell also slows down the write speeds and causes more wear in general.

Performance-wise, the Samsung 840 is actually worse than the previous generation Samsung 830. On the Passmark benchmarks, it is slightly lower than the OCZ Agility 4 which uses asynchronous MLC NAND flash.

Right now, the top three SSDs (best selling and best reviews) on Amazon are the OCZ Vertex 4, Samsung 830, and the Crucial M4. However, all three of these SSDs are cheaper and they perform better than the Samsung 840. Eventually, the TLC NAND should mean that the Samsung 840 will sell for less because less NAND is used. However, it is not worth it right now. To be safe, I would say that you should wait until the drive is at least 10-20% cheaper than the three drives above due to the uncertainty of how it will perform in the long run.

One puzzling thing is that I couldn't find any mean time before failure (MTBF) estimates for the 840, while the MTBF for the 20nm MLC based 840 Pro is 1.5 million hours (lower than the 2 million hours for many 25nm MLC drives). Also, it is interesting that the drives are not 128GB, 256GB, 512GB. There are probably three reasons for this. The TLC NAND manufacturing process has lower yields so they have to "turn off" a portion of the cells to account for this. This is similar to what Nvidia does for their GPUs (16 functional streaming multiprocessors become GTX 580, 14-15 functional streaming multiprocessors become a GTX 570, etc...) Another possibility is that they anticipate that there will be more wear to the TLC NAND so that there is an unused memory bank to replace any dead cells. The third and most likely reason is a combination of the two, i.e. a portion of the turned off cells are nonfunctional due to the new manufacturing process and the remaining portion of the turned off cells are reserved for replacement.

I handle tech purchase decisions for my department and so I bought one Samsung 840 to test for due diligence but won't buy more until they become much cheaper.


12/4/12 Update

As predicted, these drives dropped in price quite a bit. TLC NAND is about 25% cheaper than MLC NAND so that the price of these drives should converge to a ratio of around 75% of the price of a MLC SSD in the long run.
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on December 24, 2012
***UPDATE 12/31/12***
Amazon keeps removing my links in this review, sorry. Also, I notice I had my read and write speeds flopped, this has since been corrected on all my reviews posted for each SSD.

I am an avid MacBook Pro user and do a lot of hardware reviews for Apple products. I was able to get my hands on a dozen or so SSDs and test them out on a 2011 13" MacBook Pro and a 2012 13" MacBook Pro and have posted my results below on speeds, firmware and RMA.

All test were done with the SSD installed in the Main HDD Bay1, not the Optical Bay with SATA III on both the 2011 and 2012 MacBook Pro's. All 3rd party SSDs in Mac's require a Terminal CMD or TrimEnabler App to enable TRIM has OS X doesn't turn this on be fault.


*WRITE: 306.3 MB/s
*READ 486.1 MB/s

SandForce SF-2200

Cannot be updated in OSX natively, you must use a Windows PC or with Bootcamp using the Windows Update Tool found at [...]
Offers Advance RMA? Yes.

Great SSD with good speeds, not faster than the Samsung 830, 840, 840 Pro or OCZ Vertex 4 but faster than the Crucial M4. SandForce based SSD which I've seen performance issues on OS X. As you see from the Benchmarks, all the non SandForce Controlled SSDs tend to performance slower on Mac's, minus the Crucial M4. Reliability seems to be reported good with these drives and users seem to be happy overall.

*WRITE: 265.4 MB/s
*READ: 501.9 MB/s


Can be updated in OSX with a USB Drive or CD Disc using these instructions [...]

Offers Advance RMA? No

Great SSD, fast enough, good reputation for reliability. Slower than the Samsung 840 Series both Pro and Non and slower than the OCZ Vertex 4, but who will notice that besides hardcore enthusiast and benchmark braggers?

*WRITE: 472.2 MB/s
*READ: 429.9 MB/s


Easily updated for the Mac with their MacTools [...] [...]

Offers Advance RMA? Yes.

One of the fastest for PC or Mac. This thing is amazingly fast as well. OCZ hasn't had the great reputation for reliable SSDs, but since they acquired Indilinx and stopped using the SandForce controller they have gained a lot of the SSD market back and have far more reliable SSDs. They have great customer service and easy firmware updates for Mac users.

*WRITE 314.1 MB/s
*READ: 506.6 MB/s

Samsung MDX

Cannot be updated in OSX natively, you must use a Windows PC or with Bootcamp using Samsung's Magician software.

Offers Advance RMA? No

Not as fast as the Pro but still fast enough and a very reliable SSD. Samsung has a great SSD Memory Controller and provides excellent SSDs that have a great reputation for reliability.

*WRITE: 495.8 MB/s
*READ: 518.5 MB/s

Samsung MDX

Cannot be updated in OSX natively, you must use a Windows PC or with Bootcamp using Samsung's Magician software.

Offers Advance RMA? No

One of the fastest and most reliable SSDs on the market for PC or Mac. This thing is amazing and this is by far my favorite SSD. Samsung has a great SSD Memory Controller and provides excellent SSDs that have a great reputation for reliability.

*WRITE: 261.7 MB/s
*READ: 480.3 MB/s


According to SanDisk the Firmware can be updated natively on a Mac via these instructions, but I haven't tested it.

Offers Advance RMA? No

Not as fast as some of ther other SSDs but fast enough none the less. SandForce based SSD which I've seen performance issues on OS X. As you see from the Benchmarks, all the non SandForce Controlled SSDs tend to performance slower on Mac's, minus the Crucial M4. Reliability seems to be reported good with these drives and users seem to be happy overall.
3838 comments| 218 people found this helpful. Was this review helpful to you?YesNoReport abuse
on March 2, 2013
After I bought one to replace the HD in my laptop, I liked it so much, I bought another to replaced the HD in my desktop PC. I could not believe the increase in performance, especially with SATA3.

The instructions that come with it are less than helpful, so here's what I would recommend:

1) Forget about the instructions and the CD that come with it. Just go to the Samsung website ([...]) and download the Magician software and the Data Migration software.
2) Before you do anything, clean up your existing hard drive. Cleanup temporary files, clear browser caches, and get rid of old system restore points. (I would even recommend turning off system restore, but you may want to wait until after you have the SSD installed). Obviously, you'll need to get it below the capacity of the new SSD so everything will fit.
3) Reboot your PC and go into the system BIOS. Make sure your SATA interface is set to use AHCI instead of IDE mode. Reboot.
4) Defrag your hard drive. I recommend Defraggler ([...]).
5) Disable the Windows Disk Defrag automated task (you should not defrag SSDs-- it reduces their lifespan), and uninstall Defraggler if you installed it-- you won't need it anymore.
6) Install the Magician and Data Migration software from the Samsung site. The Magician won't be used until after you have the SSD installed, but you may as well install it now.
7) Shut down any other running programs (backups, Office Apps, browsers, etc.) You don't want your hard drive to be changing at all while you are copying the data to the SSD.
8) Connect the SSD to your computer via an external USB/SATA cable or available SATA connector.
9) Run the Data Migration Tool, to copy the contents of your existing HD (source) to the SSD (target). This will likely take a few hours. Don't do anything else on your computer while this is working. Once the copy is complete, the program will tell you to shutdown.
10) Shutdown the computer, remove the old HD and replace it with the new SSD.
11) Reboot the PC. You should notice Windows starts a lot faster! It will probably load some new drivers and make you reboot a couple times.
12) Launch the Magician, and use set the OS Optimization (I chose Max Performance). It will make you reboot again.
13) Launch the Magician again, and it will probably tell you there is a Firmware Update. Install the new firmware, and reboot again.
14) Launch the Magician again, and set the Over Provisioning.
15) Run the Performance Optimization in the Magician.
16) Run the Performance Benchmark, and see how fast your new drive is!
17) You can remove the Data Migration software-- you won't need it anymore.

That's it! Enjoy your new speedy computer!
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on April 12, 2013
I bought this drive to migrate my OS from HDD to SSD. I believe the process would have been smoother if Samsung had just provided the correct software package. The unit I received came with a CD with "manual & Software" (box indicated "migration software") and what you get is a package called "magician software". I installed it and when I went to the clone option, it tells me that I need to install "Norton Ghost" through a download link included in the software.

I downloaded the Norton software only to find that the cloning feature is disabled because it requires an activation key which IS NOT included in the software package that Samsung provides. I called Norton only to be on hold for a long time and then speak with a fellow which may well be in another country well known for hosting call centers. This gentleman could not help me.

While on hold, I found a useful forum where another person as myself had gone through the same steps and offered the best solution:

1. go to
2. sign up and register your product
3. after registering, go to your registered products page.
4. on this page you will find downloads for your product
5. download the available migration software (not the magician)
6. install the software
7. run it and you are done.

I do not understand why they simply don't bundle this instead of this convoluted magician thing that has no built in migration software.

I give the product 3 stars because of how this company has managed to waste 3 hours of my time between installing the drive, loading useless software x 2 (the Samsung + Norton), calling Norton for nothing, researching the web for a solution, and lastly the time to uninstall the 2 programs and clean my registry before I could even start to clone the device.

One more thing, for those with little computer experience, the instructions are not clear either. they are limited to illustrations and do not specify that the drive must be first initialized (which is something basic if you have ever added HDD to a computer)

I hope that this is useful for anyone buying this drive
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on November 8, 2012
I have the very first Macbook (intel core duo), and kicked myself back in 2006, when the duo core 2 model was released a month later.
Anyway I held on to my Macbook, and it has been used every single day since.
I decided to replace the original 60G toshiba hard drive, and what a blessing.
My Macbook uses SATA 1, rated for 1.5 Gb/s, this drive is SATA III, rated for 6 Gb/s. Therefore, I expected marginal performance.

So here is marginal for ya:
Start-up, literally 20 seconds, nearly instant shutdowns. Apps open very fast, internet web pages load a lot faster, especially with graphics and java/javascripts/flash

I'm using MAC OS 10.6.8 (Snow Leopard), TRIM is enabled, but only for Apple hard drives. A nice program called "Trim Enabler" the old version (1.2), will modify a few kernel extensions to get it to work for you. You need put in your favorite search engine "Trim Enabler 32-bit Support". Be careful not to upgrade to 10.7 / 10.8 with the 32-bit software installed.

Hopefully I can get 6 more years outta my Mac. :)
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on June 2, 2013
O.K. This drive worked great for the first two months. Purchased in mid-March 2013, and on the evening of May 24 2013, the drive failed to be recognized by my motherboard. BTW, 2010 MacBook Pro 15" with 2.66 i7 and 8 gigs of ram. This failure occurred after a week of freeze-ups after waking from sleep. I'd log into my MBP, and about a minute later it would freeze. Finally after a week of this and having to hard-reboot, the drive failed to be recognized.

After a night of recovering my TimeMachine data onto my old drive, I was back in business as before. Monday morning, I finally was able to get through to Samsung's SSD department (Yes, you must call the number, Monday-Friday from 9 am to 6 pm ET in order to RMA) and by the mid-afternoon had my RMA materials and UPS shipping label. Dropped off by 4pm, they received it the next day and had my replacement (refurbished) unit out the door to me. It arrived within 2 business days of me shipping it, however I didn't get it until the next day due to not being home at the time (requires signature).

After an evening of installing from my notebook's old OS, updating to the newest OS (it wouldn't recover from TM) and reinstalling my saved data, I was up and running perfectly again. This time faster... I pause here because it wasn't even a day of use after receiving it that it started to freeze again. This time, after 3 hard-reboots the drive failed.

I'd question software/firmware compatibility issues here. But it worked great for two months!!! No problems experience with the brand new unit purchased from Amazon. But searching any forms doesn't reveal any common problems. Perhaps my refurb unit suffered a similar freezing fate, only to be done-in again.

Allas, I am calling them in the morning and asking for a refund. There is no reason why any drive should fail this quickly (I understand issues of quality & compliance), let alone 2 in a row. I do not recommend this product. Wait for a new version, or purchase a unit from other manufacturers that are known for quality and reliability over performance (I chose this unit because it is a newer unit with impressive results and seemed to have a good track record).

I will update anything that occurs over the next few days/weeks on my experience here. For now, I'll hold my breath for a refund...

Edit #1: 3 June 2013: I finally got my refund process going. They use a third party to process RMA requests for their SSDs. I was referred to their "Executive Customer Relations Department" to go further. This business (Total Tech Solutions) didn't include a case # with the emails, only the RMA #. This caused confusion within their standard procedures to process the refund. After 2 hours on the phone with Samsung (1 dropped hold caused me to start over with waiting nearly 15 minutes to be the next in line), I await for the refund department to send me return information to proceed. The refund DOES NOT include tax or shipping charges, only the original purchase price (must submit receipt; a PDF works for speedy service). I will update once the process is complete.

Edit #2: 10 June 2013: Well, lets just say that Samsung customer service is great to work with. However, they are absolutely stuck within their "policies" even though warranty states otherwise.

I waited a week to hear what my next steps would be in initiating my refund request without hearing a thing. I called this morning and spent another 1 1/2 hours on the phone, only to find out that Samsung is absolutely unwilling to issue a refund for this product, even though it does not perform as intended!!! Well, let me restate this, IT DOES NOT WORK! It is a product that I deem DOA. All drives should function for a considerable amount of time. 2 months for the first unit is not acceptable. 2 days for the refurbished unit that I received in exchange is by NO means acceptable. In addition, Samsung is stuck within their "corporate policies", by that the ECR (Executive Customer Relations) Department is unable and unwilling to issue any refunds on Samsung SSD drives. The SSD Department is only able to issue exchanges.

That said, I am not left with seeing if Amazon is kindly able to issue a refund for this product. I feel terrible about seeking their assistance, but it is what the Samsung customer service said for me to do. "See if the retailer is willing to give a refund"..... Doesn't sound like a good way to operate a business.

I will keep updating this review once my endeavor is complete. In the mean time, I downgrade this product to NO STARS... yet I am unable to do so.

Edit #3: 17 June 2013: I must say that the reviews should include overall support from Amazon. They were extremely helpful and kind on the phone in regards to this product. They initially refunded with a restocking fee, but stated that is typically standard automated process. Just had another quick and kind phone call to discuss the results of Samsung's product, and Amazon was more than willing to refund the entire amount paid for this product.

While I reserve the right to review all products individually, the service provided by Samsung on the full warranty on this product is incomplete. Amazon greatly deserves a customer service award in serving their customers, unlike Samsung and their support for the SSD drives.
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on October 31, 2013
It worked great when I first got it. 4 months later it failed. Amazon won't let me return or exchange because it's been 4 months. Samsung is giving me the run-around on their warranty. If you get one that works, it's a great product.

I didn't have TRIM support enabled. I would suspect that other reviewers stating their drives died within a few months suffered from the same problem. Samsung eventually sent me another drive and the tech support informed me about enabling trim on the Mac OS. Newer Mac OS automatically support TRIM. The replacement Drive has been working incredibly well with TRIM support enabled for over a year now.
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on June 22, 2013
I bought a 12.7mm caddy for my old hdd to substitute my optical driver, and put this ssd on primary position.
I don't have a SATA3 motherboard yet, but it is visible the improvement in writing/reading with SATA2.

Here is some advice for you, reading all those 'steps to install ssd':
-Ignore all of them. Just change your hdd for your ssd and make a clean windows installation.
-Format it, install windows and it's done. No Samsung software, no migration software, no registration.
This is the BEST (and most secure) way to do it.
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on September 27, 2013
I had rated this drive at 5 stars. It worked great, until it started to have hang ups.. The system events log was showing "The IO operation at logical block address <number> for Disk <number> was retried." It was rather annoying, steam downloads would stop stating a hard drive error had occurred, and every time it restarted the download it would hang again and need to restart. It was annoying, but there were work-arounds. Then the explorer.exe starting to freeze up for a few seconds at a time, then chrome started to freeze up for seconds at a time. Finally the computer would not start up. Windows 8 would try to load for 10+ mins and blue-screen and restart the machine. Eventually I gave up and installed windows on a new drive, hoping only the windows section was unusable. NOPE, just trying to access the drive now fails. It cannot be read by my windows 8 machine or my windows 7 machine. All that sucks, but hey it happens, drives fail. What really bothers me is the support for this drive.

The web support for this drive is a complete joke. The forms on the website will not allow me to email them about the product. I have tried from multiple different pages, but each time one drop-down or another fails to have options in it, stopping all progress through the forms. I tried the online chat only to learn that they don't support this product via online chat. I tried the DIY troubleshooting guide only to find the entire guide literally empty. So now I need to physically call during business hours and wait on hold forever to explain my technical issue verbally to someone whom I assume will need to transfer me to someone else, repeat one to two more times. Awful experience incoming tomorrow..

TLDR: buy a drive from a company that is used to supporting hard-drives or just pray that yours never breaks.
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on September 4, 2013
I bought this for my MacBook Pro (late 2011 model) and LOVED IT - it really sped up my computer, made it feel like brand new.

However, this past weekend, it started to behave erratically -2 or 3 random errors- and then just died. It no longer boots the computer and can't even be recovered as an external device. Everything that was on the drive is gone.

Of course, the return window for Amazon expired on July 1 so now I'll have to deal with getting it replaced through Samsung (not that Samsung will be a problem, but no one can compete with Amazon for super-fast return/exchanges).

Unfortunately, I had to reinstall my original hard drive and have rediscovered just how painfully slow it is. That means I'll probably buy another SSD...maybe a different make/model?

Truly disappointing.
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