Original Link: https://www.anandtech.com/show/9704/plextor-m6v-ssd-review



Plextor's M6V SSD was originally planned to be their first drive using TLC NAND, but that has now been put off to next year's M7V. Instead, Plextor is taking advantage of a surprise hit in the SSD controller market, Silicon Motion's SM2246EN controller. We've previously tested this controller in the ADATA Premier SP610, the Transcend SSD 370, the Mushkin Reactor, and the Crucial BX100. The SM2246EN was designed to be a low-power controller for low-cost drives, and it has been very successful in that segment. The controller doesn't support TLC NAND, so all of these drives are free of the higher power consumption and lower performance that have troubled low-end TLC solutions we've seen so far.

SM2246EN SSDs
Drive NAND Capacites
ADATA Premier SP610 Micron 128Gbit 20nm MLC 128GB, 256GB, 512GB, 1TB
Transcend SSD 370 Micron 128Gbit 20nm MLC 32GB, 64GB, 128GB, 256GB, 512GB, 1TB
Mushkin Reactor Micron 128Gbit 16nm MLC 256GB, 512GB, 1TB
Crucial BX100 Micron 128Gbit 16nm MLC 120GB, 250GB, 500GB, 1TB
Plextor M6V Toshiba 128Gbit 15nm MLC 128GB, 256GB, 512GB

The SM2246EN has been paired with a variety of NAND, so these drives don't all perform identically. The Plextor M6V is the first time we've seen this controller paired with Toshiba's 15nm MLC, which is significantly denser than Micron's planar NAND and competitive with Samsung's second generation V-NAND. Toshiba has had trouble getting the 15nm MLC out the door in large quantities, and the rest of Plextor's products are still using Toshiba 19nm or A19nm MLC.

Of the major SM2246EN drives, each one differs a bit from the others in terms of features. Transcend's SSD 370 and its aluminum-clad variant (the SSD 370S) use custom firmware to offer encryption, but is missing some power saving modes. Mushkin's Reactor was initially available only in the 1TB capacity, but the 512GB and 256GB models are now available from some retailers. Crucial's BX100 uses semi-custom firmware and features the partial power loss protection now typical of their mainstream drives. The Plextor M6V, by comparison, has just the basic feature set of a SM2246EN drive, augmented only by Plextor's PlexTurbo RAM caching software for Windows (but not Windows 10).

Plextor has opted to not make a 1TB version of the M6V, which would probably require more expensive packaging to fit on the PCB layout they're using. Our 256GB sample has 8 packages on front of the PCB and 8 empty pads on the back, which means that each package has two 128Gbit dies inside.

Plextor M6V SSD Specifications
Size 128GB 256GB 512GB
Controller Silicon Motion SM2246EN
NAND Toshiba 15nm Toggle MLC
DRAM Cache 128 MB 256 MB 512 MB
Sequential Read 535 MB/s 535 MB/s 535 MB/s
Sequential Write 170 MB/s 335 MB/s 455 MB/s
4kB Random Read 81k IOPS 83k IOPS 83k IOPS
4kB Random Write 42k IOPS 80k IOPS 80k IOPS
Warranty 3 years

The M6V also has siblings in smaller form factors: the M6MV (mSATA) and M6GV (M.2 SATA), both using the same controller and flash as the M6V. They shouldn't be confused with the M6M and M6G, Plextor's higher-performance mSATA and M.2 SATA drives, which like the rest of Plextor's SSDs use Marvell controllers and 19nm Toshiba flash. The M6MV doesn't have a 512GB configuration, but the M6GV does. Both of the smaller form factors use more expensive and denser BGA packaging for the NAND flash, and neither seems to be readily available for purchase yet.

AnandTech 2015 SSD Test System
CPU Intel Core i7-4770K running at 3.5GHz (Turbo & EIST enabled, C-states disabled)
Motherboard ASUS Z97 Deluxe (BIOS 2401)
Chipset Intel Z97
Chipset Drivers Intel 10.0.24+ Intel RST 13.2.4.1000
Memory Corsair Vengeance DDR3-1866 2x8GB (9-10-9-27 2T)
Graphics Intel HD Graphics 4600
Graphics Drivers 15.33.8.64.3345
Desktop Resolution 1920 x 1200
OS Windows 8.1 x64


Performance Consistency

Our performance consistency test saturates the drive with 4kB random writes for a full hour, with a queue depth of 32, the maximum supported by the AHCI protocol used by SATA and most PCIe drives. This puts the drive's controller under maximum stress and writes enough data to exhaust all free space and spare area on the drive. This is an unrealistic workload for any client use, but it provides a worst-case scenario for long-term heavy use, and it sheds light on how different SSD controllers behave and if their performance will hold up as they fill up.

The average of the last 400 seconds of the test gives us a steady-state IOPS rating that is usually very different from what the manufacturer specifies for a new, empty drive. We also quantify the consistency of the drive's random write performance, and provide plots of the performance over the course of the test.

Steady-State 4KB Random Write Performance

The M6V's steady-state performance falls well behind the Crucial BX100 and only slightly ahead of drives using TLC NAND, pointing to either significant firmware differences or lower performance from the Toshiba 15nm MLC than Micron's 16nm MLC.

Steady-State 4KB Random Write Consistency

Plextor is able to eke out a little more consistency from the SM2246EN, but unfortunately this is due to the best-case being worse, rather than a significant improvement in the worst-case IOPS.

Plextor M6V 256GB
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Looking at the whole duration of the test, we see that once the M6V is filled and performance takes a nosedive, the M6V has a very slow recovery toward its steady state of occasionally reaching around 15k IOPS. Like the BX100, it has a pretty solid baseline and there are no garbage-collection pauses that drop it in to hard drive territory.

Plextor M6V 256GB
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AnandTech Storage Bench - The Destroyer

The Destroyer is an extremely long test replicating the access patterns of heavy desktop usage. A detailed breakdown can be found in this review. Like real-world usage and unlike our Iometer tests, the drives do get the occasional break that allows for some background garbage collection and flushing caches, but those idle times are limited to 25ms so that it doesn't take all week to run the test.

We quantify performance on this test by reporting the drive's average data throughput, a few data points about its latency, and the total energy used by the drive over the course of the test.

AnandTech Storage Bench - The Destroyer (Data Rate)

The M6V falls in the middle of the pack for its capacity class, and again its performance is a little behind its sibling with the same controller.

AnandTech Storage Bench - The Destroyer (Latency)AnandTech Storage Bench - The Destroyer (Latency)AnandTech Storage Bench - The Destroyer (Latency)

The middling to poor latency results echo the poor write performance consistency, but these results are nothing too concerning for a client drive designed for a typical consumer workload.

AnandTech Storage Bench - The Destroyer (Power)

The SM2246EN continues to deliver impressive power efficiency, though again the BX100 beats the M6V.



AnandTech Storage Bench - Heavy

Our Heavy storage benchmark is proportionately more write-heavy than The Destroyer, but much shorter overall. The total writes in the Heavy test aren't enough to fill the drive, so performance never drops down to the steady state. This test is far more representative of a power user's day to day usage, and is heavily influenced by the drive's peak performance. The Heavy workload test details can be found here.

AnandTech Storage Bench - Heavy (Data Rate)

On an empty drive, the M6V performs almost identically to the Crucial BX100 and several other drives, but when starting with a full drive the M6V suffers more.

AnandTech Storage Bench - Heavy (Latency)

The average service time doesn't differentiate the M6V much from its neighbors on this ranking.

AnandTech Storage Bench - Heavy (Latency)

There's a marked difference in the number of latency outliers for the M6V and all of the drives below it on this chart. The M6V's higher average service time is due to it being consistently a little slower than the BX100, rather than occasionally a lot slower.

AnandTech Storage Bench - Heavy (Power)

The M6V has now very slightly surpassed the BX100 to take the top spot for power consumption.



AnandTech Storage Bench - Light

Out Light storage test has relatively more sequential accesses and lower queue depths than The Destroyer or the Heavy test, and it's by far the shortest test overall. It's based largely on applications that aren't highly dependent on storage performance, so application launch times and file load times are what dominate this test. Details of the Light test can be found here.

AnandTech Storage Bench - Light (Data Rate)

The M6V is almost exactly tied with the BX100 for average data rate, indicating that their peak performance is essentially the same.

AnandTech Storage Bench - Light (Latency)

The M6V is ranked second to last in average service time, but the SATA drives are all performing nearly the same.

AnandTech Storage Bench - Light (Latency)

AnandTech Storage Bench - Light (Power)

The M6V is again using the least power, though its advantage over the BX100 is about as small as our equipment can measure.



Random Read Performance

Our random read performance test is conducted on a full drive and tests queue depths from 1 to 32. We focus primarily on the lower queue depths that are typical of interactive use, but also look at how the performance and power scales to more intensive loads. For desktop use, searching and virus scanning are typically the biggest sources of random reads, and they can exercise some of the larger queue depths.

Iometer - 4KB Random Read

The M6V posts above average performance on the random read test, and is clearly better tuned for it than the Crucial BX100.

Iometer - 4KB Random Read (Power)

The power consumption and thus efficiency here are significantly better than the competition.

Plextor M6V 256GB
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The M6V scales well with increasing queue depths, and its high rating above comes mostly from its good performance with queue depths of 2 and 4. Power consumption starts low and only grows slightly.

Random Write Performance

The random write test is confined to a 16GB portion of the drive, which is otherwise empty. This allows the drive to demonstrate much higher performance than on our performance consistency test that fills the drive. Tasks like installing software updates can modify a lot of files, but aren't hitting the entire disk. Random writes to the entire disk are usually found only in enterprise workloads such as large databases.

Iometer - 4KB Random Write

The M6V falls back to being one of the slowest MLC drives, but the spread among 240-256GB drives isn't huge.

Iometer - 4KB Random Write (Power)

The lower performance again brings power savings, showing that the M6V is pretty well optimized, just not for peak performance.

Plextor M6V 256GB
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Many drives of this size hit a performance limit somewhere along this test, but the M6V scales smoothly across the range of queue depths. However, the overall increase is small and the lower queue depths are left lacking.



Sequential Read Performance

Just like the random read test, sequential reads are tested across the span of a full drive and a representative sample of queue depths. Most operations involving large files (typically images and videos) fall under this test's purveiw, but streaming or playing even the highest resolution videos won't be a challenge for any of these drives. Copying files to another SSD or loading a new level in a video game would be more likely to show noticeable difference from better performance here.

Iometer - 128KB Sequential Read

The SATA interface's speed limit determines almost everything in this graph. Almost all drives, including the M6V, are close enough that the differences hardly matter.

Iometer - 128KB Sequential Read (Power)

On the other hand, power consumption varies considerably. The TLC drives are at the bottom as usual, and the M6V is at the top with only a little bit of competition.

Plextor M6V 256GB
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The queue depth scaling reveals the source of the variation in the averages above. The only drives below the M6V in performance are the ones that can't hit the limit at a queue depth of two, and the drives above the M6V all have better QD 1 performance.

Sequential Write Performance

The sequential write isn't limited to a small span of the disk, as that usually doesn't make a difference for this performance metric. As always, our averages are of the lower queue depths, but scaling to higher queue depths is also investigated. Bulk file copies and recording uncompressed video are the kind of uses that depend on sequential write performance.

Iometer - 128KB Sequential Write

The M6V is back in the middle of the pack, and none of the SATA drives of this size are quite able to reach the limit of the interface.

Iometer - 128KB Sequential Write (Power)

The M6V doesn't quite take first place for power consumption, but it comes within spitting distance of the surprisingly efficient Samsung 850 EVO.

Plextor M6V 256GB
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Most drives have flat performance across this test, indicating that a 128kB block of data is already large enough for the drive to extract all the speed it can.



Mixed Random Read/Write Performance

Most real-world use consists of a mix of reads and writes, and interleaving the two often poses a particular challenge to drive controllers. This mixed random access test is conducted across a 16GB span of the drive, but on a full drive and with a queue depth of 3.

Iometer - Mixed 4KB Random Read/Write

Once again the M6V is in the top performance tier, but is the slowest of that bunch. The SATA interface isn't even close to being a limitation here.

Iometer - Mixed 4KB Random Read/Write (Power)

The slight degree to which the M6V lags behind the performance of the BX100 is made up for by the power savings.

Plextor M6V 256GB
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Performance is pretty flat across this test, and the power consumption grows slowly as more writes are thrown in to the mix. The OCZ Vector 180 pulls ahead on the strength of its performance in the 100% write test, while the Crucial BX100 and Samsung 850 EVO are helped by stronger performance in the read-heavy parts of the test.

Mixed Sequential Read/Write Performance

The queue depth of 3 is sufficient for many drives to perform very well at either end of this test, while testing 100% reads or 100% writes. In between, performance typically suffers greatly, and that's where the winners and losers of this test are determined. Anything that's duplicating duplicating or transforming a large amount of data on the drive will produce I/O patterns similar to this test. Creating a System Restore snapshot, backing up files to a different directory on the same drive, and file compression can all produce interleaved reads and writes of large blocks of data, though not necessarily fast enough to be limited by the drive's performance.

Iometer - Mixed 128KB Sequential Read/Write

The Crucial BX100 performed very well on this test, but the M6V is only average here.

Iometer - Mixed 128KB Sequential Read/Write (Power)

The M6V is once again solidly in the lead for power consumption, and is well ahead of even the BX100.

Plextor M6V 256GB
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The M6V drops just below 150MB/s during the worst parts of this test, then recovers well as the workload shifts toward pure writes. Its relatively low performance on the 100% read and 100% write portions of the test are keeping the average down.



ATTO - Transfer Size vs Performance

ATTO provides a quick and easy test of performance over a range of block sizes, which makes it a good overview of performance. It illustrates quite clearly how performance plateaus as transfer size increases, with reads bumping up against the limits of SATA but writes being limited by the speed of the flash itself.

AS-SSD Incompressible Sequential Performance

Any drives that perform transparent compression will perform much worse on this test than the Iometer tests. The SandForce controllers that relied heavily on compression are much less popular (having been largely displaced by controllers from Silicon Motion, Marvell, and Phison), but this in still an important metric to keep in the suite. Many real-world sources of bulk data (such as encoded video) are already heavily compressed and cannot benefit from any attempts at further compression.

Incompressible Sequential Read PerformanceIncompressible Sequential Write Performance



Idle Power Consumption

Many SATA drives are getting close to the limits of what our equipment can measure for power consumption. It's hard to build a meter than has sub-milliwatt accuracy and can withstand the high peak currents drawn by devices like high-performance PCIe drives. Our test rig can't measure the deepest power saving modes (DevSlp), but we can look for any red flags that the intermediate modes aren't working.

Idle Power Consumption (HIPM+DIPM)

At this point in the review, it's obvious that the M6V has no trouble keeping power consumption down. There is technically room for improvement here, but not enough to matter.

TRIM Validation

A drive that didn't correctly implement the ATA TRIM command would be very surprising to find today, but it's a quick enough check. This test also demonstrates that, for better or worse, files that are deleted cannot be easily recovered.



Final Words

The value-oriented segment of the SSD market has a lot of great options at the moment for drives that don't have any critical weaknesses or major compromises relative to high-end SATA drives. This means that buying decisions will be driven almost entirely by the pricing of the moment. If priced properly, the Plextor M6V can be a great choice for general-purpose consumer use and especially for mobile use.

From a technical perspective, the most interesting aspect of the M6V is its Toshiba 15nm MLC NAND, as this is the only SM2246EN-based drive using it. Toshiba's 15nm MLC NAND seems to be a bit slower than the Micron 16nm MLC used in its closest relatives/competitors, but at the same time the M6V uses a bit less power. These differences are measurable, but probably not meaningful in the real world. The Plextor M6V and Crucial BX100 are about as close to interchangeable as drives can be without being clones that differ by only their label. The BX100's partial power loss protection may be important to some consumers but it's usually not a requirement in this market segment, and SM2246EN drives have not had any notable reliability issues.

Amazon Price Comparison (10/12/2015)
Drive 120/128GB 240/250/256GB 500/512GB 960GB/1TB
ADATA Premier SP610 $49.99 $84.99 $223.44 $379.99
Transcend SSD 370 $57.99 $89.99 $169.99 $328.46
Mushkin Reactor - - - $353.99
Crucial BX100 $61.99 $79.99 $159.99 $314.99
Plextor M6V $65.99 $99.99 $189.99 -
OCZ Trion 100 $59.95 $75.00 $158.99 $349.90
Samsung 850 EVO $64.00 $89.24 $168.63 $343.24

Unfortunately, the current pricing on the Plextor M6V is simply too high in a crowded market. It's undercut by the Crucial BX100 and Samsung 850 EVO at every capacity point, and even the older SM2246EN drives using 20nm MLC are cheaper. Crucial and Samsung have the advantage of in-house NAND manufacturing, but the other competitors are just as much at the mercy of their NAND supplier as Plextor. In the long run the Toshiba 15nm MLC in the M6V ought to allow Plextor to beat ADATA and Transcend on price thanks to its greater density, but at these prices Toshiba and Plextor aren't there yet.

Ultimately if the high price is due to limited supply of the 15nm MLC, there may be significant price cuts further down the road as they get production ironed out. For now, although the M6V is as solid as any of the other SM2246EN drives, overall the BX100 remains the better value. Otherwise Plextor still has a hand to play in the market for smaller form factors; if the mSATA and M.2 variants of the M6V show up along with more reasonable pricing, they'll be very compelling for power-sensitive uses, as the BX100 is only available in the 2.5" form factor.

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