For the longest time now, entry-level solid-state drive (SSDs) have all been 2.5-inch SATA drives, because the 2.5-inch form factor has been around forever (or at least since the late 1980s), and most users looking for a low-cost SSD are probably rocking a PC with a standard hard drive bay that can take one.
But that's quickly changing, now that even budget laptops and convertibles are getting increasingly slim, leading to the proliferation of the M.2 connector and the naked-circuit-board M.2 drives that plug into them. Some of the benefits of this form factor are that drive makers don't have to pay for an enclosure, and there are no cables to worry about, either. Most new gaming and enthusiast-grade desktop motherboards are also adding M.2 connectors for storage. So it's not too difficult to imagine a future in which SATA connectors mostly disappear and M.2 dominates (unless you need several storage drives, in which case you might buy a specialty board or an add-in card for that purpose).
Plextor certainly is looking ahead, as its new S2G M.2 SSD (we specifically tested the 256GB PX-256S2G, $85 street price at this writing) is astride both present and future. It uses both the old SATA interface and the new M.2 form factor. It's a reasonably affordable upgrade option for those looking to switch from a 2.5-inch drive to an M.2 model in a new or existing desktop, or swap in something more spacious in a recent laptop or convertible. (For more details and an explanation of the jargon surrounding the shifting SATA/PCI Express/NVMe tides of M.2 SSDs, check our roundup The Best M.2 Solid-State Drives.)
The S2G uses low-cost TLC NAND flash, which has become the favored choice for cost-conscious SSD models, due to its balance of reasonably good performance and affordability. All of this adds up to make the S2G an unusual SSD. Why? It's marketed as an entry-level drive, thanks to its TLC flash, and yet it uses the still fairly uncommon M.2 form factor, but in SATA trim instead of the PCI Express/NVMe interface of performance-focused drives such as the Samsung SSD 960 Pro. Plextor also makes a model in the familiar 2.5-inch chassis, dubbed the S2C. (Perhaps the "C" stands for "classic?")
Similar Products
Samsung SSD 960 EVO
Samsung SSD 850 EVO (500GB)
Crucial BX300 (240GB)
ADATA Ultimate SU800 (512GB)
Since this is a "naked" M.2 drive, there's not much of interest to look at on the drive itself. It's an M.2 Type-2280 SSD, which means it's 22mm wide and 80mm long—the most common size for M.2 drives when we wrote this in early 2017. The S2G is essentially a printed circuit board with a few TLC NAND flash chips on it from SK Hynix and a Silicon Motion controller, so there's not much else to say in terms of the drive's aesthetics.
This version comes in a simple transparent-plastic container, too. So, from top to bottom, this drive was designed to be affordable, with little attention paid to presentation. Even the version in a 2.5-inch enclosure is just solid silver, with no racing stripes, flame graphics, or other niceties.
Still, despite the Plextor S2G's plain appearance, it is using the latest in 16nm planar TLC NAND, and though the flash isn't stacked vertically like Samsung has been doing for a few years now, the storage here should be fast enough for most home users. In case you don't know what TLC NAND is, it's basically a type of memory that packs more bits per cell than MLC (which used to be far more common in SSDs). This allows for higher capacity with fewer chips, letting companies like Plextor reduce costs, which are then passed onto the consumer in the form of a really affordable SSD.
Samsung pioneered TLC technology in 2013 with its SSD 840 Series drive (and soon after, the SSD 840 EVO), and it has since become synonymous with entry-level and mainstream drives, due to its low cost and adequate all-around performance, sort of like a four-cylinder engine for cars or integrated graphics on PCs. Better options are available in all these areas for those who need more power or speed. But for most consumers, TLC (like integrated graphics and the straight-four engine) is good enough to get the job done.
As for the drive on hand, the S2G is available in 128GB, 256GB, and 512GB capacities. Interestingly, the drive doesn't employ any overprovisioning, so you get more usable storage for your buck. Typically, an SSD will have some capacity set aside to allow for the drive to manage itself (sort of like a large swap file), so if the controller needs to move things around, it has some fresh memory cells to put things in while it reorganizes its data.
Plextor claims its use of an "SLC cache" mechanism allows it to bypass this typical setup. So, instead of getting a 120GB drive, you get a 128GB drive, 256GB instead of 240GB or 250GB, and 512GB instead of 480GB or 500GB. Plextor does indeed have a point that most SSDs don't offer up their full capacity for storage, but we've also always thought overprovisioning was a necessity on an SSD.
Plextor claims it has developed a workaround, which it calls PlexNitro technology. The company claims this is also a workaround for the slower write-performance issues related to the use of TLC NAND (which are a fact of life with this type of memory). Basically, Plextor is claiming other companies use overprovisioning to sidestep these write-performance issues. But every manufacturer we know of that uses TLC NAND uses both an SLC cache and overprovisioning too. So we aren't sure how Plextor gets away with using just one of these two common TLC tools. Regardless, Plextor's drives do have a little more capacity than other TLC SSDs; there's no arguing with that.
Plextor has also come up with a DRAM-caching solution dubbed PlexTurbo, which seems similar to what Samsung has allowed on its drives for a few generations now with its RAPID Mode. It allows the system to cache writes to system memory to overcome the SATA interface's performance limitations, with the downside being any sudden power outage (say, a failing battery in a laptop) could jeopardize any data that is in-flight, sitting in your system's RAM. We don't have empirical evidence that this actually improves SSD "feel" in the real world, but it can make for some sky-high benchmark scores. What's interesting about Plextor's description of its caching solution is that it recommends users have 32GB of RAM. How many people buying a low-cost, entry-level SSD are going to have that much memory? Not many, we would wager. Note that, just as with Samsung SSDs that support the similar RAPID Mode, we didn't test the Plextor drive with this caching feature turned on. If we did so, we'd effectively be testing the speed of our testbed's RAM, not the abilities of the drive itself.
Since the Plextor S2G is a SATA drive, its performance specs are pretty similar to other midrange SATA drives. The drive is rated to reach 520MB per second in sequential-read speeds and 450MB per second in sequential writes. That's not as fast as a drive like the Samsung SSD 850 Pro or SSD 850 EVO. But again, this is a lower-priced SSD designed for first-time upgraders, not performance enthusiasts. So we're not knocking Plextor for the fact that this drive isn't expected to compete with the fastest SATA-based drives available.
The S2G includes a three-year warranty, which is standard for drives of this class. As far as pricing goes, we gathered some intelligence from Newegg, Amazon, and elsewhere, and found the 128GB version of the Plextor S2G selling for $45, the 256GB version going for $85, and...that's all we could find for the M.2 version. A 512GB version was for sale at $139, but we only saw it in the 2.5-inch form factor when we wrote this.
Overall, these are very low prices on a per-gigabyte basis, but it's hard to find a plethora of M.2 SATA drives for comparison, as there still aren't that many. There are SSD 850 EVO drives with this configuration, though, and the 250GB SSD 850 EVO was about $10 more expensive than the Plextor when we wrote this. The real bummer for Plextor is the fact that the 275GB version of the Crucial MX300 in M.2 trim is widely available for around $90 or a little less, offering up extra capacity for just a few dollars extra.
Performance Testing
If you're new to the world of SSDs, a few things are worth noting when it comes to performance. For starters: If you're upgrading from a standard spinning hard drive, any modern SSD will be a huge improvement, speeding up boot times and making programs launch faster. Though the drive on hand makes use of the M.2 form factor, most of today's SSDs do not. But they do use the same base interface, which is called SATA III (also called "6Gbps SATA"), to achieve maximum speed.
We test all of our 2.5-inch SATA SSDs on a SATA III-equipped testbed PC to show their full performance abilities, and you'll see a subset of those numbers here as a comparison for this Plextor M.2 drive, which was tested on our newer M.2 testbed. That system employs an MSI Z97 motherboard with a 240GB SATA 6Gbps SSD as its boot drive. (The M.2 drives, like the 2.5-inch SSDs we test, are tested as secondary storage drives, not boot drives.)
We started seeing SATA-based M.2 slots on Haswell-based Z97 motherboards, and many boards with the Z170 and Z270 chipsets (as well as enthusiast X99 boards) offer M.2 ports. But many of those ports connect to the much faster PCI Express bus instead of SATA, and may or may not work with SATA drives. (Some boards have M.2 connectors that do work with both SATA and PCIe drives, but not PCIe NVMe drives.) As always, check carefully with your PC's manufacturer or consult your motherboard's manual to see what ports you have, what interface they use, and what types of drives are recommended before you spend any money. And again, for a refresher about what all this means, be sure to check the lengthy explainer at the beginning of our M.2 SSD roundup The Best M.2 Solid-State Drives.
PCMark 7 (Secondary Storage Test)
The Secondary Storage Test is a subtest under Futuremark's larger PCMark 7 benchmarking suite. It employs a different approach to drive testing than pure speed tests like AS-SSD, which we'll get to next. PCMark 7 runs a series of scripted tasks typical of everyday PC operation and disk accesses. It measures app launches, video-conversion tasks, image import, and more. The result is a proprietary numeric score; the higher the number, the better.
This score is useful in gauging general performance versus other drives. Note that we secure-erase all SSDs before running PCMark 7's Secondary Storage Test.
The S2G started out looking reasonably good here, landing in the lower-middle of our chart, above the Crucial MX300. The MX300 has a similar marketing appeal as the S2G, in that it's offered as a "good enough" SSD at a very affordable price. We'd also be remiss if we didn't point out the Samsung 850 EVO lingering in the bottom half, so it seems like the drives at the nether regions of this chart aren't automatically slow drives, by any means. It's just that the top half is dominated by PCI Express-based drives that, by nature, will dominate any set of SATA-interface drives.
AS-SSD Sequential Read & Write Speeds
The AS-SSD benchmark utility is designed specifically to test solid-state drives (as opposed to traditional hard drives). It reports a variety of scores, but the ones we are reporting in these two charts below measure a drive's ability to read and write large files. Drive makers often quote sequential speeds, as a theoretical maximum, on the packaging or in advertising. Sequential speeds are important if you're working with very large files for image or video editing, or you play lots of games with large levels that take a long time to load with traditional hard drives. We secure-erase all SSDs using the utility Parted Magic before running this test.
Those PCI Express SSDs are making the SATA drives look bad on this chart, but most SATA drives end up being able to read sequentially at a bit above 500MB per second, which is where the Plextor is at here. Once again, the Plextor S2G drive rides above the Crucial MX300 and the Samsung SSD 850 EVO.
The S2G finally shows its budget focus here, landing near the bottom compared to drives we've tested recently. But it was able to perform to spec and even beyond it a bit (remember that Plextor rates writes at up to 450MB per second), so these results are expected. Most recent SATA drives land between 450MB and 500MB per second when it comes to writes, with only Kingston's SM2280S3 in this bunch landing well below that mark.
AS-SSD 4K Read & Write Speeds
This test, also a part of the SSD-centric AS-SSD benchmark, measures a drive's ability to traffic small files. Often overlooked, 4K performance, particularly 4K write performance, is quite important when it comes to boot speed and program launch times.
When an SSD is booting up and launching programs, many tiny files get accessed and edited frequently. The faster your drive can write and read these kinds of files (especially dynamic link library, or DLL, files in Windows), the faster your OS will "feel." Since these small files are accessed much more frequently than large media or game-level files, a drive's performance on this test will have a greater impact on how fast a drive feels in everyday use.
In this random read test, the S2G placed near the bottom of the chart, with a score of 33.5MB per second. But once again, the Samsung SSD 850 Pro is just a couple rungs below it. That anomaly aside, the S2G is right alongside older SATA SSDs like its good buddies the Kingston HyperX Savage and the Crucial MX200, which seems about right. Since the S2G isn't aiming to be a chart-topping performer, it makes sense that it would perform about the same as a high-end SATA SSD from a year or two ago.
If this review has taught us anything so far, it's that the Plextor S2G ends up next to the Samsung SSD 850 Pro and EVO a lot more than we anticipated. In this test, it's sandwiched between them, edging out the SSD 850 Pro and getting pipped by the EVO by a few megabytes per second.
What's odd is that there are several SATA SSDs that were able to perform much better than the Plextor S2G and its cohorts on this test, including the similarly budget-price Crucial MX300. At first, we thought that the TLC/SLC cache nature of the Plextor drive and the Samsung SSD 850 EVO might be what's holding them down here. But the SSD 850 Pro that landed second-to-last on this test uses 3D-stacked MLC NAND. Perhaps the Samsung Pro drive's just showing its age. It is now about 2.5 years old, which is a long time in SSD years.
Crystal DiskMark (QD32 Testing)
Crystal DiskMark uses incompressible data for testing, which stresses most modern SSDs quite a bit since they rely on data compression to achieve their maximum level of performance. This particular test is designed to replicate the duties of an SSD located inside a Web server, as it's asked to perform a smattering of small reads, which are 4K in size. While it's reading these files, there is a queue of 32 outstanding requests lined up, which is normal for a high-volume Web server, which has to fulfill requests that all come in at the same time from various clients.
Though the SATA drives look slow now that the PCI Express drives have been added to our M.2-drive benchmark charts, this chart shows how close they perform to each other on high-queue-depth tasks. When it was just SATA drives on this chart, small differences between them appeared much larger. But now it's much more apparent that the differences aren't really that large. We can also see that the Plextor S2G is once again adjacent to the Samsung SSD 850 EVO and Crucial MX300, so its performance is quite good.
On this test, we can clearly see the Plextor S2G is in fact slower than its counterparts, as random writes are tough on any SSD, and a test like this tends to highlight that fact. What's different this time around, though, is that one of the only modern drives that performed similarly to the S2G is the Crucial MX300, which again, is a "good enough"-class SSD for basic upgrades. Most of the other SATA drives here were quite a bit faster.
Conclusion
The Plextor S2G M.2 SSD isn't an exciting drive in either its performance numbers or its aesthetics. Other than a tiny Plextor logo on its sticker, it has no branding whatsoever. It's made from off-the-rack parts (though with custom firmware), and it seems to be basically an OEM replacement part designed for a laptop or convertible.
You could buy one and put it in your desktop, but we suspect Plextor's parent company Lite-On will sell most of these drives to laptop manufacturers in volume, if for no other reason than there's nothing in the drive's packaging or performance to make it stand out from flashier, similarly priced competition meant for DIY upgraders or PC builders. The S2G offers decent performance for a SATA drive, usually slightly outpacing our current favorite budget drive, the Crucial MX300. But it's not the fastest SATA drive of its kind, by any measure.
For desktop users, even those with a SATA-capable M.2 connector, some similarly performing 2.5-inch drives cost a little less and perform similarly. So, unless you're out of SATA ports and places to mount traditional 2.5-inch drives, you're better off going that route.
On the other hand, if you own a laptop or convertible with a SATA M.2 slot, there's probably already an SSD installed in it, so there's no real point in "upgrading" to another SATA drive unless you just need extra capacity. And with the S2G topping out at 512GB (if you can even find it at that capacity), it's not ideal for those who want a spacious boot drive. For that, Western Digital's WD Blue SSD is a better option, as it's available in capacities up to 1TB in the same M.2 form factor. The WD Blue is also reasonably priced (as well as being a fine midrange performer).
If it was our purchasing decision, and we had to go with an M.2 SATA drive in these midsize capacities, we'd get the Crucial MX300, just because it offers a higher capacity (275GB) for about $5 more than the 256GB Plextor drive. Or, for $10 more than the Plextor drive, you could pick up the 250GB Samsung SSD 850 EVO for its excellent software package and longer five-year warranty.
The Plextor PX-256S2G is a fine performer in the budget space. But for appearance-conscious desktop DIY types installing the drive in a PC with a windowed chassis, it doesn't offer much in the way of style (unlike the pricier Plextor M8Pe M.2 NVMe SSD), and it doesn't strongly undercut competing drives on price. While the SATA-bus M.2-based competition may still be a little light, Plextor needs to offer up a little more in the S2G drive (or lower its price by $10 or more) if it wants this drive to stand out.
Like What You're Reading?
Sign up for Lab Report to get the latest reviews and top product advice delivered right to your inbox.
This newsletter may contain advertising, deals, or affiliate links. Subscribing to a newsletter indicates your consent to our Terms of Use and Privacy Policy. You may unsubscribe from the newsletters at any time.
Thanks for signing up!
Your subscription has been confirmed. Keep an eye on your inbox!
Sign up for other newsletters
