Review Index:

Crucial MX300 750GB 2.5" SATA SSD Review - 3D NAND on a Budget

Subject: Storage
Manufacturer: Crucial

Introduction, Dynamic Write Acceleration, and Packaging


Micron joined Intel in announcing their joint venture production of IMFT 3D NAND just a bit over a year ago. The industry was naturally excited since IMFT has historically enabled relatively efficient production, ultimately resulting in reduced SSD prices over time. I suspect this time things will be no different as IMFT's 3D Flash has been aiming high die capacities since its inception, and I suspect their second generation will *double* per-die capacities while keeping speeds reasonable thanks to a quad-plane design implemented from the start of this endeavor. Of course, I'm getting ahead of myself a bit as there are no consumer products sporting this flash just yet - well not until today at least:

View Full Size

Marketed under Micron's consumer brand Crucial, the MX300 is their first entrant into the consumer space, as well as the first consumer SSD sporting IMFT 3D NAND. Crucial is known for their budget-minded SSDs, and for the MX300 they chose to go with the best cost/GB they could manage with what they had to work with. That meant putting this new 3D NAND into TLC mode. Now there are many TLC haters out there, but remember this is 3D NAND. Samsung's 850 EVO can exceed 500 MB/sec writes to TLC at its 500GB capacity point, and this MX300 is a product that is launching with *only* a 750GB capacity, so its TLC speed should be at least reasonable.

(the return of) Dynamic Write Acceleration

View Full Size

Dynamic Write Acceleration in action during a sequential fill - that last slowest part was my primary concern for the mX300.

TLC is not the only story here because Crucial has included their Dynamic Write Acceleration (DWA) technology into the MX300. This is a tech where the SSD controller is able to dynamically switch flash programming modes of the flash pool, doing so at the block level. This appears to be a feature unique to IMFT flash, as every other 'hybrid' SSD we have tested had a static SLC cache area. DWA's ability to switch flash modes on-the-fly has always fascinated me on paper, but I just haven't been impressed by Micron's previous attempts to implement it. The M600 was a bit all over the place on its write consistency, and that SSD was flipping blocks between SLC and MLC. With the MX300 flipping between SLC and *TLC*, there was a possibility of far more noticeable slow downs in the cases where large writes were taking place and the controller was caught trying to scavenge space in the background.

View Full Size

New Latency Percentile vs. legacy IO Percentile, shown here highlighting a performance inconsistency seen in the Toshiba OCZ RD400. Note which line more closely represents the Latency Distribution (gray) also on this plot.

Read on for our full review of the Crucial MX300 750GB SATA SSD!

Upon our initial sampling and testing of the MX300, I noted some of the odd behavior that I had feared. Sometimes we reviewers can catch odd behaviors not anticipated by the manufacturer, feed those issues back, and get tweaks implemented prior to launch. We helped OCZ tweak some issues with their Vector 180 prior to launch (though they couldn't correct the issue completely). I had better luck back with my first ever review of the Intel X25-M long-term performance issue - caused by a bug that was found and ultimately squashed by Intel. The story with the MX300 is, thankfully, another one of those successes. A few of my peers reported inconsistencies with DWA's initial tuning, and I was able to work closely with the Micron / Crucial team to report back my findings, ultimately resulting in firmware updates and a better performing product. I'd also like to credit the MX300 for prompting me to improve upon our Latency Percentile results. It was their specific firmware oddity (now fixed) that highlighted some issues with our legacy IO-weighted percentile plotting method), and the resulting improvements yielded something that could more easily and directly demonstrate the issue at hand to their engineers. Major kudos to the Micron / Crucial team for stepping up and taking immediate action. After working with their team it is clear to me that their priority is to get things as right as they possibly can *before* releasing a product to market.

Detailing the tweaks made, the improved DWA is still very much dynamic but is a bit more reserved on how aggressively it chooses its SLC mode for flash pool allocation. The controller will do its best to maintain at least 10GB of SLC for host writes, and during idle periods will shuffle data if necessary as to clear up SLC-mode blocks once the SSD is mostly filled (even a full MX300 will attempt to keep at least 10GB of SLC caching capability). The advantage to DWA over SSDs with static SLC caches is that the MX300 doesn't have to constantly empty that cache. If the SSD is only half full, it can just leave some data in SLC areas and simply flip some other TLC blocks into SLC mode, instantaneously creating more cache. As the SSD becomes filled with user data over time, the controller may have to go back and open up some more TLC space, but in most cases this will be transparent to the user. Benchmarking is a bit of a worst-case scenario here, but Crucial have also made tweaks that recognize heavy sustained writing activity, and the controller can preemptively shift to TLC writing as to avoid the need to later shuffle blocks around in the background - a task that would normally slow writes to a crawl.


View Full Size

This is a budget SSD, and the packaging is certainly sparse. A 7mm to 9.5mm spacer is still included, as well as an Acronis True Image HD license for cloning your existing install to the MX300.

Video News

June 14, 2016 | 08:11 AM - Posted by Anonymous (not verified)

Nice price, but too small. :(

June 14, 2016 | 12:56 PM - Posted by Anonymous (not verified)

your not going to be seeing really high capacity coming to these budget drives for a while. most of the industry is stuck at 1tb with only high end drives going further like the 850 pro. Once 480gb drops to the current 250gb prices then i would imagine 2tb and higher drives coming to take the top spot

June 14, 2016 | 11:36 AM - Posted by Doeboy (not verified)

Why can't somebody make a cheap 2tb SSD?!!!

June 14, 2016 | 11:42 AM - Posted by Anonymous (not verified)

Because it's a waste of money to store pr0n movies... ;-)

June 15, 2016 | 04:59 PM - Posted by Doeboy (not verified)

Actually, if you're a pcgamer then you want 2tb otherwise you'll have to uninstall and reinstall games to make room. 1tb is not enough, especially with newer games that take up a lot of space.

June 15, 2016 | 06:14 PM - Posted by Anonymous (not verified)

Even PC gamers are wasting their money for loading faster huge games from SSD with no performance gain in game. ;-)

You should better use a HDD for massive storage like games or movies. If the cost doesn't matter you should be able to buy any SSD capacity or quantity.

June 14, 2016 | 12:01 PM - Posted by DJ (not verified)

These charts that you are using are absolutely horrible to read. For example, that HDTach chart, the read and writes should be separated and then the results should be ranked going from best to worst. Actually.... any results chart you have should be ranked from best to worst. That way you can easily see how thing compare. Those YAPT charts.... tell me nothing. I can't tell the difference between any of them really. And have you guys ever stopped to think for a moment about someone who is color blind? Trying to find which line goes to what would be impossible. Even without the color issue it's still pretty bad.

Been meaning to say this stuff for a while. I honestly have had to skip right to your conclusions in your product reviews because the data charts are just god awful. Please make this info easier to read.

June 14, 2016 | 01:02 PM - Posted by Allyn Malventano

Most of that testing is being phased out. If you can't tell the difference in YAPT, that means all SSDs are saturating SATA (a good thing). There is really nothing we can do about colors in charts, unfortunately. Regarding sort order, keeping the subject of the article at the top keeps it more easily identifiable. People have to dig to find the new product in sorted charts, and coloring it differently clashes with your colorblind comment...

June 16, 2016 | 12:14 PM - Posted by DJ (not verified)

You don't have to keep it at the top. If sort the chart and highlight the new product then it's easy to see. Guru3D has been doing their charts this way for years. It also makes it much easier to see how x product compares to y product. The non sorted charts are a mess and it's very hard to see how products compare.

June 14, 2016 | 01:45 PM - Posted by phillychuck

$200 for 750gb, does that mean on sale $150? I've been seeing lots of 960gb drives on sale for $180-$200 lately.

Allyn, why has there been no new SATA standard? NVME interfaces don't seem to be the greatest, M.2 is great but what if I want 2-3 drives?

I don't like RAID because I like to be able to break up the band without a big headache, or not seem to screw up my array when I flash a new BIOS.

June 14, 2016 | 02:21 PM - Posted by Allyn Malventano

There are motherboards with 3 m.2 slots, and they don't have to be in a RAID to be used. Additional m.2 devices can also be installed via adapter cards, etc. Sadly, PCIe is the way things are moving, and SATA 6Gbit may be the last iteration of it that we see in the wild.

June 15, 2016 | 07:35 AM - Posted by Pixy Misa (not verified)

I'd like to see USB 3.1 / Type C replace SATA. It's faster, delivers power and data over the same compact connector, and can do PCIEx4 in alt mode.

And you don't need drive cases. Just plug the bare drive straight in to any available port.

June 15, 2016 | 01:35 PM - Posted by phillychuck

That would be a cool idea, I'm not a fan of external boxes all over the place. I still like the tower case with plenty of expansion ports/drive bays. Yes, I still rocking the optical. I saw a post somewhere, the guy complained that he was installing an OS and it needed drivers for USB ports, but he had his drivers on a USB drive. I guess out of luck.

I wonder why no faster SATA, they can't come up with a better shielded cable and up the clocks?

June 16, 2016 | 10:54 AM - Posted by Maximilian Schmitt (not verified)

I've read elsewhere on forums covering this release that the MX300 "Appears to be underwhelming". Another response stated, "Underwhelming is being polite".

Could this be because they analyzed the product before you're aforementioned fixes were implemented?

What's the deal with the controller? Does Micron potentially have a better one around the corner and that is why they are classifying the MX300 as 'Limited Edition' so as not to hamper current sales?

All input is appreciated. Thanks for your great article :)

June 16, 2016 | 11:00 AM - Posted by Maximilian Schmitt (not verified)

What'd I'd really like to know is if IMFT's Floating Gate Technology on their 3D NAND is really going to materially increase performance or if it is just reducing power consumption and improving efficiency, as has been the case with DRAM every year.

Will Micron 3D NAND Product blow planar NAND out the water or will it just strongly compete?

Max (23 yr old investor)

June 16, 2016 | 12:40 PM - Posted by Romans Pokrovskis (not verified)

I think you should draw a line of a product in review above every other lines on the graphs for better visibility

June 16, 2016 | 03:45 PM - Posted by vin1832 (not verified)

personally, i would like someone to do a video or an article dedicated to this new DWA technology
the available information out there is very limited, and may not be that reliable.

if possible, please explain, my interest on this new technology is quite high, since i've never heard of it

and also, what's up with the quad plane thing?

i hope someone explains it


June 23, 2016 | 11:54 AM - Posted by flooked92

It was linked in the article:

June 18, 2016 | 11:39 PM - Posted by HERETIC (not verified)


750 GB means there's no direct competitor.
This should really be the replacement for the BX200 (which deserves LEMON status)not the MX200-That would hopefully be replaced with 3D-MLC.................

Be interesting to see what follows-Have a feeling speeds will tank on smaller drives-Be interesting to see this size with a 8 ch controller..........

July 12, 2016 | 06:11 AM - Posted by Michael Rand (not verified)

For anyone in the UK, Amazon UK have this currently on sale for £109 in the current Prime Sale.

July 25, 2016 | 06:34 PM - Posted by funkter (not verified)

Thanks for the detailed analysis and also the very good quality pictures.


November 24, 2016 | 04:51 AM - Posted by spizzlo (not verified)

They gave it an editor's choice at $200. What about at $100? Well that's what it's going for on Amazon right now. (11-24-16 @4:00AM EST) That's $0.13/GB!!!!

November 25, 2016 | 06:41 AM - Posted by Anonymous (not verified)

yeah same, on amazon uk at £105.99 for today, seems a good deal to me :)

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Lines and paragraphs break automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd> <blockquote><p><br>
  • Web page addresses and e-mail addresses turn into links automatically.

More information about formatting options

This question is for testing whether you are a human visitor and to prevent automated spam submissions.