Original Link: https://www.anandtech.com/show/12485/the-plextor-m8v-sata-ssd-review



Today we're taking a look at Plextor's M8V SSD. This is their latest entry-level SATA SSD and the first SATA drive from Plextor to use 64-layer 3D TLC NAND flash memory.

64-layer 3D NAND flash memory started hitting the market last year, but only a handful of consumer SSDs using the latest-generation flash have launched. All of the early models came from the vertically-integrated manufacturers of flash memory and SSDs. Intel, Micron, Toshiba and Western Digital all introduced drives last year with their own 64L 3D TLC. That flash memory is now starting to be used by the rest of the market, as other brands fill in the gaps left by the biggest players.

Plextor is the consumer retail SSD brand of Lite-On, one of the largest SSD manufacturers that is not also a NAND flash manufacturer. One of Lite-On's primary ways of differentiating their SSDs is by developing in-house firmware for the SSD controllers, rather than using the reference firmware provided by most controller vendors. This means that Lite-On/Plextor SSDs often have fairly different performance profiles from drives that at first glance seem to be almost identical technologically.

Plextor M8V Specifications
Capacity 128 GB 256 GB 512 GB
Form Factor 2.5" SATA and M.2 2280 SATA
Controller Silicon Motion SM2258
NAND Toshiba 64-layer 3D TLC
Sequential Read up to 560 MB/s up to 560 MB/s up to 560 MB/s
Sequential Write up to 400 MB/s up to 510 MB/s up to 520 MB/s
4KB Random Read  up to 60k IOPS up to 81k IOPS up to 82k IOPS
4KB Random Write  up to 70k IOPS up to 80k IOPS up to 81k IOPS
Endurance 70 TBW 140 TBW 280 TBW
Warranty 3 years

The Plextor M8V is a budget-oriented SATA SSD using Toshiba's 64L 3D TLC. Where Toshiba's own TR200 adopts a DRAMless controller to cut costs, the Plextor M8V uses the mainstream Silicon Motion SM2258 controller. That controller is used in the Crucial MX500, one of the best mainstream SATA SSDs on the market today. A derivative—the SM2259—is used in the Intel 545s. Plextor isn't trying to position the M8V directly against those drives or other top-tier SATA SSDs, but they will still be some of the primary competition for the M8V. The Crucial MX500 will also be one of the more interesting drives to compare the M8V against in terms of performance and power consumption, because the shared controller gives us the opportunity to judge whether Micron or Toshiba's 64L 3D TLC is better.

Our test sample is the 2.5" 512GB M8V. The M.2 version should perform almost identically and use about the same power, and the smaller capacities will definitely be slower—especially the 128GB models. The Plextor M8V features a three-year warranty, but the write endurance ratings are more in line with drives that have five year warranties.

The M8V uses the same brushed aluminum case that Plextor has been using for generations. Inside, we find a small PCB with markings that indicate the M8V is the alter ego of the Lite-On CV8 client SSD for the OEM market. There are two NAND packages on each side of the PCB, and a Samsung DRAM part next to the SM2258 controller. The M8V does not use any thermal pads.

AnandTech 2017/2018 Consumer SSD Testbed
CPU Intel Xeon E3 1240 v5
Motherboard ASRock Fatal1ty E3V5 Performance Gaming/OC
Chipset Intel C232
Memory 4x 8GB G.SKILL Ripjaws DDR4-2400 CL15
Graphics AMD Radeon HD 5450, 1920x1200@60Hz
Software Windows 10 x64, version 1709
Linux kernel version 4.14, fio version 3.1


AnandTech Storage Bench - The Destroyer

The Destroyer is an extremely long test replicating the access patterns of very IO-intensive desktop usage. A detailed breakdown can be found in this article. Like real-world usage, 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. These AnandTech Storage Bench (ATSB) tests do not involve running the actual applications that generated the workloads, so the scores are relatively insensitive to changes in CPU performance and RAM from our new testbed, but the jump to a newer version of Windows and the newer storage drivers can have an impact.

We quantify performance on this test by reporting the drive's average data throughput, the average latency of the I/O operations, and the total energy used by the drive over the course of the test.

ATSB - The Destroyer (Data Rate)

The Plextor M8V has a slower average data rate on The Destroyer than most current drives, but it is clearly faster than the models using Micron's older 32L 3D TLC. The DRAMless Toshiba TR200 is by far the slowest current-generation SSD.

ATSB - The Destroyer (Average Latency)ATSB - The Destroyer (99th Percentile Latency)

Average and 99th percentile latencies from the M8V are a bit on the slow side. The average latency bridges the gap between the top tier of drives and the handful that have significant trouble with this test.

ATSB - The Destroyer (Average Read Latency)ATSB - The Destroyer (Average Write Latency)

The average read latency from the M8V is on the high side of normal for mainstream SATA drives, and the average write latency is a bit worse than the normal range for current-generation SATA drives.

ATSB - The Destroyer (99th Percentile Read Latency)ATSB - The Destroyer (99th Percentile Write Latency)

The 99th percentile read latency from the M8V is among the worst in this class of drives. The 99th percentile write latency is also high, but is still small compared to the DRAMless Toshiba TR200.

ATSB - The Destroyer (Power)

The energy used by the Plextor M8V over the course of The Destroyer is a bit more than normal for this class of drives, as expected given the slower performance than most other 64L 3D TLC drives.



AnandTech Storage Bench - Heavy

Our Heavy storage benchmark is proportionally 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 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. This test is run twice, once on a freshly erased drive and once after filling the drive with sequential writes.

ATSB - Heavy (Data Rate)

The Plextor M8V has a slower average data rate on the Heavy test than most mainstream SATA SSDs, but it retains almost all of that performance when the test is run on a full drive. This gives it a clear advantage over last-generation drives like the Crucial MX300 and ADATA SU800 that have higher peak performance but don't hold up well under pressure.

ATSB - Heavy (Average Latency)ATSB - Heavy (99th Percentile Latency)

The average and 99th percentile latencies of the Plextor M8V on the Heavy test are higher than for any of its current-generation competitors, but the M8V isn't one of the huge outliers.

ATSB - Heavy (Average Read Latency)ATSB - Heavy (Average Write Latency)

Both the average read latency and average write latency scores from the M8V are slightly higher than normal for mainstream SATA drives, but the differences aren't big enough to worry about.

ATSB - Heavy (99th Percentile Read Latency)ATSB - Heavy (99th Percentile Write Latency)

The 99th percentile read latency of the M8V is unusually poor, matching the Plextor S2C and substantially exceeding all the competitors, even the Toshiba TR200. The 99th percentile write latency is not an extreme outlier, merely a bit higher than what the top-tier SATA drives provide.

ATSB - Heavy (Power)

The energy usage by the Plextor M8V on the Heavy test is clearly higher than most SATA drives, but by a fairly small margin.



AnandTech Storage Bench - Light

Our 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 this is a test more of application launch times and file load times. This test can be seen as the sum of all the little delays in daily usage, but with the idle times trimmed to 25ms it takes less than half an hour to run. Details of the Light test can be found here. As with the ATSB Heavy test, this test is run with the drive both freshly erased and empty, and after filling the drive with sequential writes.

ATSB - Light (Data Rate)

As with the Heavy test, the average data rate of the Plextor M8V on the Light test is a bit on the slow side, but the M8V does quite well under the extra pressure of running the test on a full drive.

ATSB - Light (Average Latency)ATSB - Light (99th Percentile Latency)

The average latencies from the Plextor M8V are a bit higher than normal, but not to a great extent, and the full-drive score is pretty good. The situation for 99th percentile latencies is worse, with the M8V showing much higher tail latencies than most current SATA SSDs.

ATSB - Light (Average Read Latency)ATSB - Light (Average Write Latency)

The average read and write latencies from the Plextor M8V are both a bit higher than most drives but not enough to be a noticeable problem. The average read latency is more clearly lagging behind the competitors.

ATSB - Light (99th Percentile Read Latency)ATSB - Light (99th Percentile Write Latency)

The 99th percentile read latency of the Plextor M8V is a problem—5.6ms is quite a bit slower than the 2-3ms that most SATA SSDs manage. The 99th percentile write latency of the M8V is also higher than most drives, but it doesn't stand out as such a clear outlier.

ATSB - Light (Power)

The energy usage of the M8V on the Light test is only slightly higher than normal for the other Silicon Motion-based drives, and for SATA SSDs in general.



Random Read Performance

Our first test of random read performance uses very short bursts of operations issued one at a time with no queuing. The drives are given enough idle time between bursts to yield an overall duty cycle of 20%, so thermal throttling is impossible. Each burst consists of a total of 32MB of 4kB random reads, from a 16GB span of the disk. The total data read is 1GB.

Burst 4kB Random Read (Queue Depth 1)

The burst random read performance of the Plextor M8V is slightly slower than the other current mainstream SATA SSDs, but it is clearly faster than the drives using Micron's 32L 3D NAND.

Our sustained random read performance is similar to the random read test from our 2015 test suite: queue depths from 1 to 32 are tested, and the average performance and power efficiency across QD1, QD2 and QD4 are reported as the primary scores. Each queue depth is tested for one minute or 32GB of data transferred, whichever is shorter. After each queue depth is tested, the drive is given up to one minute to cool off so that the higher queue depths are unlikely to be affected by accumulated heat build-up. The individual read operations are again 4kB, and cover a 64GB span of the drive.

Sustained 4kB Random Read

On the longer random read test, the Plextor M8V places just behind the Crucial MX500—it's again slower than its peers, but only to a small degree in this case.

Sustained 4kB Random Read (Power Efficiency)

The Plextor M8V's power efficiency during the random read test is better than that of most drives using older NAND generations, but is the worst among the drives using 64L 3D TLC.

At QD1 and QD2, the random read performance of the Plextor M8V is competitive with most SATA SSDs. At QD4 and above, it starts to fall behind the high-end drives, but for most consumer workloads that won't matter much.

Random Write Performance

Our test of random write burst performance is structured similarly to the random read burst test, but each burst is only 4MB and the total test length is 128MB. The 4kB random write operations are distributed over a 16GB span of the drive, and the operations are issued one at a time with no queuing.

Burst 4kB Random Write (Queue Depth 1)

The Plextor M8V has top-notch burst random write performance, showing that the drive's SLC write cache is very quick.

As with the sustained random read test, our sustained 4kB random write test runs for up to one minute or 32GB per queue depth, covering a 64GB span of the drive and giving the drive up to 1 minute of idle time between queue depths to allow for write caches to be flushed and for the drive to cool down.

Sustained 4kB Random Write

On the sustained random write test, the Plextor M8V falls back dowwn to the middle of the pack, but it manages to have very small leads over both the Crucial MX500 and Intel 545s.

Sustained 4kB Random Write (Power Efficiency)

The Plextor M8V is more power efficient for random writes than the Intel 545s but otherwise its efficiency lags behind the other drives of its generation.

Like most drives in its class, the Plextor M8V's random write performance is mostly saturated by around QD4. The performance at high queue depths is well below that of the Samsung drives or the peak eventually reached by the Crucial MX500, but the Plextor M8V performs fine for a low-end drive.



Sequential Read Performance

Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.

Burst 128kB Sequential Read (Queue Depth 1)

The Plextor M8V has great burst sequential read performance, but most mainstream SATA drives also perform close to this level.

Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data.

Sustained 128kB Sequential Read

On the longer sequential read test, the Plextor M8V is no longer one of the top drives but its performance is still respectable even by the standards of modern 64L 3D TLC drives.

Sustained 128kB Sequential Read (Power Efficiency)

The Plextor M8V's power efficiency during sequential reads is good. Samsung's drives and Toshiba's DRAMless drives are more efficient, but among other mainstream SATA SSDs the M8V comes out on top.

In absolute terms the power consumption of the M8V is higher than most other SATA drives, but the performance is high enough to largely justify the power consumption.

Sequential Write Performance

Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.

Burst 128kB Sequential Write (Queue Depth 1)

The Plextor M8V is in a multi-way tie for second fastest burst sequential write speed. Since the top-scoring Samsung 850 PRO is on its way out, that puts the M8V in the top tier of current SSDs.

Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.

Sustained 128kB Sequential Write

The sustained sequential write speed of the Plextor M8V reminds us that the M8V is still an entry-level SSD with some pitfalls. The M8V isn't anywhere near as slow as the TR200 or the Plextor S2C, but it can't keep up with the mainstream SATA SSDs or some of the other budget SSDs.

Sustained 128kB Sequential Write (Power Efficiency)

The power efficiency of the M8V during sustained sequential writes is relatively low, but doesn't stand out as badly as its performance score.

While clearly on the slow side, the Plextor M8V's sequential write performance is steady, with most of its performance available at QD1 and there are no signs of major problems managing the SLC cache.



Mixed Random Performance

Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.

Mixed 4kB Random Read/Write

The mixed random I/O performance of the Plextor M8V is decidedly low-end, though still twice as fast as the Toshiba TR200 which is handicapped by a DRAMless controller.

Mixed 4kB Random Read/Write (Power Efficiency)

Power efficiency from the Plextor M8V is also poor, but there are a few more drives that core near the  M8V on efficiency than there were for performance.

The Plextor M8V's performance on the random I/O test dips slightly as writes are added to the mix, and performance is slow to recover. The Crucial MX500 is slightly faster across the board, but its power consumption doesn't have a clear advantage through all phases of this test.

Mixed Sequential Performance

Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.

Mixed 128kB Sequential Read/Write

The mixed sequential I/O performance of the Plextor M8V is only slightly below average for mainstream SATA drives, and is about the same performance as the Crucial MX500.

Mixed 128kB Sequential Read/Write (Power Efficiency)

The power efficiency of the M8V during the mixed sequential I/O test was good—only slightly worse than the Intel 545s, though well behind Samsung and the DRAMless SSDs.

The performance of the Plextor M8V decreases steadily through most of the mixed sequential I/O test, reaching a minimum fairly late in the test when the I/O mix is very write-heavy. When the workload finally transitions to pure writes, the speed picks up a bit, but not enough to bring the average back up very far. The power consumption bottoms out with a 50/50 read/write mix.

The scaling behavior of the M8V most closely resembles Samsung's SATA drives, but they tend to retain more of their performance during the first half of the test, and recover more performance after hitting their low in the second half.



Power Management

Real-world client storage workloads leave SSDs idle most of the time, so the active power measurements presented earlier in this review only account for a small part of what determines a drive's suitability for battery-powered use. Especially under light use, the power efficiency of a SSD is determined mostly be how well it can save power when idle.

SATA SSDs are tested with SATA link power management disabled to measure their active idle power draw, and with it enabled for the deeper idle power consumption score and the idle wake-up latency test. Our testbed, like any ordinary desktop system, cannot trigger the deepest DevSleep idle state supported by many drives.

Active Idle Power Consumption (No LPM)Idle Power Consumption

The half watt active idle power consumption of the Plextor M8V is not great, but is a fairly typical value. Most drives using the SM2258 controller draw a bit more power than the M8V.

When the SATA link power management is enabled, the M8V ends up drawing a few mW more than most of the other drives with the same controller, and is substantially more power hungry than the best SATA SSDs.

Idle Wake-Up Latency

The Plextor M8V's idle wake-up latency of about 1.2ms is about average for SATA SSDs, and reasonable given the power savings achieved by the sleep state. Several other drives like the Crucial BX300 and ADATA sU800 have managed much faster wake-up times from the same SM2258 controller.



Conclusion

In terms product positioning, the Plextor M8V is a value-oriented product. However positioning can be deceiving, and as we've seen on many tests the M8V punches well above its weight, matching the performance of top-tier SATA drives. The overall picture is that the M8V is generally a bit slower and less power efficient that most of the other recent SSDs using 64L 3D TLC NAND, but the performance gaps are never huge. Unlike many entry-level SSDs, the M8V retains almost all of its performance as it fills up; it doesn't need to be treated carefully to keep it performing well.

The Plextor M8V is the first SSD we've tested using the combination of Toshiba's 3D NAND and the Silicon Motion SM2258 controller. The other SM2258 drives we've tested recently used Intel and Micron 3D NAND, which appears to be slightly superior given the results from the M8V. But many of the differences may be due to firmware rather than inherent properties of the different 3D NAND designs.

Toshiba's own drive with their 64L 3D TLC is the TR200, which uses a DRAMless controller and clearly suffers the performance penalties that brings, but it also makes the TR200 one of the lowest-power SSDs on the market. The M8V is quite a bit faster than the TR200 and preferable in almost any use case.

Compared to the M8V, top-tier SATA SSDs like the Crucial MX500 or Samsung's 860 EVO/PRO will rarely deliver noticeable performance or battery life improvements. The M8V is good enough in both respects, even though it isn't the best.

The Plextor M8V was announced six weeks ago but is not yet available for purchase from the major online retailers. Plextor has not published official MSRPs, so we can't make any definitive buying recommendations for the M8V yet. When it does hit the shelves, the M8V may not be competitively priced at first. In today's market, being competitively priced means for the M8V that it has to undercut the Crucial MX500, currently 25–27¢/GB and with a longer warranty. The exception is the 128GB M8V which is in a capacity class with far less competition. For that model, we expect a price of around $45 (35¢/GB) would be highly competitive, but it could end up anywhere between that and the $60 the Crucial BX300 currently sells for.

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