Plextor PX-256M6M 256GB mSATA Solid State Drive

At this year's Consumer Electronics Show (CES), Plextor launched its new M6 series SSDs. Along with the 2.5-inch M6S and PCIe M6e, this multi-form factor lineup included the company's latest mSATA SSD, the M6M. Designed for ultrabooks, tablets and other portable devices with limited space, the M6M provides high-performance and reliability in a space one-eighth the size of a standard 2.5-inch SSD. The drive combines Marvell's 88SS9188 "Monet Lite" controller with Toshiba's Advanced 19nm (A19) Toggle Mode MLC NAND to deliver up to 520MB/s read and 440MB/s write transfer rates. The M6M also supports Plextor's exclusive True Speed and True Protect technologies as well as the SATA Device Sleep (DEVSLP) standard which extends the battery life of a device by reducing the drive's power consumption to 2 mW when it is not in use.

For this review, Plextor sent us the PX-256M6M. This 256GB SSD comes equipped with 512MB of on-board cache and is capable of delivering up to 520MB/s sequential read and 440MB/s sequential write speeds as well as up to 94,000 random read and 80,000 random write IOPS.

Compared to the bright yellow box that Plextor's M6S series SSDs come in, the M6M's packaging is pretty boring. The drive ships in a simple clamshell similar to what memory modules come packed in. The sticker on top shows the model, capacity, firmware version and serial number of the drive inside. It's hard to make out in these pictures, but Plextor has also managed to squeeze in the drive's specs. Inside the packaging, you'll find the drive as well as a bag containing a couple of mounting screws.

Physical Features:

The M6M follows the JEDEC MO-300 standard for mSATA SSDs. It measures a mere 50.8 x 29.8 x 3.6 mm and is about one-eighth the size of a standard 2.5-inch drive. The M6M also has a 52-pin mSATA connector which supports data transfer rates up to 6 Gb/s.

Like the M6S, the M6M uses Marvell's 88SS9188 "Monet Lite" controller. There is very little information available regarding this controller but from what we can gather from our conversations with Plextor, it is very similar to the 88SS9187 "Monet" controller found in the M5M, M5 Pro and M5Pro Xtreme. The main difference is that instead of eight NAND flash channels, the 88SS9188 supports only four.

For the PX-256M6M, Plextor has opted to use Toshiba's 64GB A19nm TH58TEG9DDKBA8H Toggle Mode MLC NAND flash chips. Looking at the pictures above, you can see that there are two of these chips on either side of the PCB. The drive also has a single 512MB NANYA NT5CC256M16CP-DI DDR3-1600 SDRAM chip that is used for caching and garbage collection.

The test system used in this review was an HP 8200 Elite. The computer came equipped with an Intel Core i5-2400 CPU, 4GB of DDR3 1333MHz memory, Seagate Barracuda 7200.12 ST3250312AS 250GB SATA 6 Gb/s hard drive, NVIDIA Quadro FX580 512MB PCIe graphics card and an Intel 82579-LM gigabit network card. For the operating system, I installed a fresh copy of Windows 7 Enterprise. I should also point out that our test system is not equipped with an mSATA port so we had to use an mSATA to SATA 6 Gb/s adapter card.

To test the performance of the Plextor PX-256M5Pro Xtreme, I ran a series of benchmarks using CrystalDiskMark 3.0.1, HD Tach RW 3.0.4.0, ATTO Disk Benchmark 2.46, AS SSD, HD Tune Pro 4.61, Anvil's Storage Utilities and Iometer. For comparison, I've also included test results from the Plextor PX-256M5M, Samsung SSD 840 EVO mSATA, OCZ Vector 150, OCZ Vertex 450, Silicon Power Slim S55, Samsung SSD 840 EVO, Seagate 600 SSD, SanDisk Extreme II, OCZ Vector, Plextor PX-256M5Pro Xtreme, Samsung SSD 840 Pro, Samsung SSD 840, Kingston Ultra Plus, OCZ Vertex 4, OCZ Agility 4 and Kingston HyperX 3K.

Like the M6S, the M5M is based on Marvel's 88SS9188 controller chip. Looking at the screenshot above, you can see that it performs equally well with both incompressible (0%) and compressible (100%) data.

CrystalDiskMark 3.0.1:

First, I ran a few quick tests using CrystalDiskMark. This benchmark tool measures the performance of a storage device by testing its sequential read and write speeds as well as its random read and write speeds using blocks 512K and 4K in size.

Plextor PX-256M6M

Plextor PX-256M5M

According to Plextor, the PX-256M6M is capable of reading at 520 MB/s and writing at 440 MB/s when connected to a SATA 6 Gb/s port. While the drive performed well, it came up a bit short of these numbers in CrystalDiskMark's sequential read and write speed tests.

Plextor PX-256M6M - All 0x00, 0Fill

Plextor PX-256M5M - All 0x00, 0Fill

The PX-256M6M performed equally well when using highly compressible 0x00 (0 Fill) data. This time around, the drive was able to read at 498.7 MB/s and write at 432.6 MB/s.

HD Tach RW 3.0.4.0:

Next, I used HD Tach to test the PX-256M6M's read, write and burst speeds as well as its seek times and CPU usage.

Looking at the screenshot above, you can see that the PX-256M6M had average read and write speeds of 418.8 MB/s and 360.9 MB/s respectively, as well as a burst speed of 364.6 MB/s.

ATTO Disk Benchmark 2.46:

I also used ATTO Disk Benchmark to test the PX-256M6M's sequential read and write speeds. The tests are run using blocks ranging in size from 0.5KB to 8192KB and the total length set to 256MB.

Plextor PX-256M6M

Plextor PX-256M5M

When tested with ATTO, the PX-256M6M's read speeds topped out at about 521 MB/s and its write speeds at 443 MB/s.

AS SSD:

AS SSD is a relatively new benchmark designed specifically for solid state drives. The application contains five synthetic tests used to determine the sequential and random read and write performance of a drive.

Plextor PX-256M6M

Plextor PX-256M5M

AS SSD also includes a copy benchmark. This test copies an ISO (two large files), program (many small files) and game (small and large files), returning the speed and duration of each.

Plextor PX-256M6M

Plextor PX-256M5M

HD Tune Pro 4.61:

Next, I ran a series of tests using HD Tune Pro. This hard disk utility measures a drive's performance by testing its sequential read and write speeds as well as its access time, burst rate and CPU usage. For this review, I'm also going to use it to benchmark the PX-256M6M's random read and write speeds, random access times and the number of operations per second.

Plextor PX-256M6M - HD Tune Read Benchmark

Plextor PX-256M5M - HD Tune Read Benchmark

Plextor PX-256M6M - HD Tune Write Benchmark

Plextor PX-256M5M - HD Tune Write Benchmark

The PX-256M6M performed very well when benchmarked with HD Tune. The drive had average read and write speeds of 497.6 MB/s and 404.2 MB/s, respectively, and a burst rate of 381.7 MB/s when reading.

Plextor PX-256M6M - HD Tune Random Access Read

Plextor PX-256M5M - HD Tune Random Access Read

Plextor PX-256M6M - HD Tune Random Access Write

Plextor PX-256M5M - HD Tune Random Access Write

The PX-256M6M didn't disappoint when doing random reads and writes. When writing 4KB blocks, the drive reached 20,040 IOPS and had an average speed of 78.283 MB/s. The PX-256M6M was even faster when reading, reaching 22,988 IOPS with an average speed of 89.799 MB/s.

Anvil's Storage Utilities:

Anvil's Storage Utilities is another new benchmark designed with SSDs in mind. The standard storage benchmark measures a drive's performance by testing its transfer speeds, access times and IOPS.

Iometer:

Lastly, I ran a series of tests using Iometer. This tool can be configured to benchmark a number of things. In this case, I used it to measure the PX-256M6M's read and write speeds and the number of operations per second. The tests were run using random bytes and a queue depth of 3.

The PX-256M6M's performance was very similar to what we saw in our other tests. The drive was able to read at 497.66MB/s and write at 421.45 MB/s.

The PX-256M6M also performed relatively well when doing random reads and writes. In our tests, the drive was able to read at 126.31 MB/s and write at 242.43 MB/s.

According to Plextor, the PX-256M6M is capable of 94,000 IOPS when reading and 80,000 IOPS when writing 4K blocks. In our tests, the drive reached 32,334 random read IOPS and 62,062 random write IOPS. The only way I came close to Plextor's numbers was to increase the queue depth. With the queue depth set to 32, the PX-256M6M reached 94,891 random read IOPS and 80,074 random write IOPS.

TRIM and True Speed:

While SSD's offer many benefits, there are some downsides to using flash memory. One of the biggest issues people run into is performance degradation. Over time, an SSD will run out of fresh blocks and will have to write over data the file system has marked as deleted. This procedure is very complicated and can slow an SSD's write speeds considerably.

To fix this problem, most manufacturers have added TRIM support to their SSDs. The TRIM command allows an operating system, such as Windows 7, to tell an SSD which data blocks are no longer in use. Using this information, the drive pro-actively erases these blocks and adds them to the free block pool.

The M6M is the latest drive to ship with their Plextor's exclusive True Speed technology. By leveraging the power of advanced firmware, True Speed ensures that the SSD works at its full potential even after extensive use and long periods of operation. Along with support for TRIM, the M6M's firmware incorporates Plextor's Bad Block Management, Global Wear Leveling and Instant Restore technologies. Where Bad Block Management and Global Wear Leveling optimize the way data is written on the drive, Instant Restore maintains "like new" performance by reorganizing data to maximize the number of free cells.

Plextor's True Speed technology works very well, as I saw very little performance degradation, even after hours of testing. I was finally able to overwhelm it by using Iometer to fill the entire drive and then running a random write test for 30 minutes. This had little impact on the PX-256M6M's read speed. However, its average writing speed dropped to 35.4 MB/s when in this "dirty" state.

Plextor PX-256M6M - Dirty

To see how well the PX-256M6M could recover, I let the computer sit for about an hour and then reran the test. Looking at the screenshot below, you can see that the drive has not fully recovered yet.

Plextor PX-256M6M - Recovering

I let the computer sit for another hour and then ran the test again. The drive still wasn't able to reach the factory fresh performance shown in our earlier tests. However, its average write speed climbed up to 410.5 MB/s.

Plextor PX-256M6M - After TRIM

Lastly, I used LtnSSD to pre-format the PX-256M6M. With the drive wiped clean, it had average read and write speeds of 418.7 MB/s and 366.6 MB/s, respectively.

Plextor PX-256M6M - Secure Erase

Final Thoughts:

Plextor has come a long way over the last few years. The company has gone from being an also ran to one of the leading innovators in the consumer SSD market. While not as revolutionary as some of Plextor's previous offerings, the M6M is the mSATA SSD to combine Marvell's 88SS9188 "Monet Lite" controller with Toshiba's new Advanced 19nm (A19) Toggle Mode MLC NAND flash. The 88SS9188 has half the NAND flash channels as the 88SS9187 "Monet" controller found in the M5M and M5 Pro. However, thanks to a custom firmware, the M6M is still able to deliver a fast, responsive computing experience. In our sequential read and write tests, the PX-256M6M was able to read at speeds as high as 521 MB/s and write at speeds in excess of 432 MB/s. It also did reasonably well our random write tests, producing more than 62,000 IOPS at low queue depths.

Impressive performance isn't the only thing the M6M has to offer. The drive supports Plextor's exclusive True Speed technology, which does a fairly good job of maintaining original performance levels, even after intensive use and long periods of operation. The M6M also features Plextor's True Protect double-data protection technology, which provides integrity checking for long-term data accuracy and 256-bit AES full disk encryption for data confidentiality. Last, but not least, the M6M supports the SATA Device Sleep (DEVSLP) standard which extends the battery life of a device by reducing the drive's power consumption when it's not in use.

The M6M is expected to ship some time in the second quarter of this year and, if the suggested retail prices of the PX-128M6M ($140), PX-256M6M ($250) and PX-512M6M ($500) are any indication, it could end up costing more than Plextor's previous mSATA SSD, the M5M. As it is, the M5M is not exactly cheap and with the mSATA versions of the Samsung SSD 840 EVO and Crucial m550 selling for as little as $0.6/GB, the M6M is going to be a tough sell, especially for consumers and enthusiasts on a budget.

Highs:

• mSATA form factor
• Available in 128GB, 256GB and 512GB capacities
• Good sequential and random read and write performance
• Performs equally well with compressible and incompressible data
• SATA 6Gb/s interface
• Toggle Mode MLC NAND flash
• Large DRAM cache
• True Speed technology provides consistent performance, even after intensive usage
• True Protect double-data protection technology
• 256-bit AES encryption
• DEVSLP power mode
• Supports TRIM, SMART and NCQ
• 3 year warranty

Lows:

• Not as fast as the M5M when reading
• Does not support TCG Opal or eDrive encryption
• Pricey