Another ultra-fast SSD with a quad-lane PCIe 4.0 interface is available today: the Adata XPG Gammix S70 is a new 80mm M.2 drive, as is the Samsung 980 Pro, WD Black SN850, and Sabrent Rocket 4 Plus, It does the job of competing with these, to name just a few of the many PCIe 4.0 drives currently available to choose from.

After all, simply offering 6 or 7 gigabytes of raw bandwidth is not enough to make this drive stand out from the PCIe 4.0 crowd. That said, we might as well square away the Adata XPG Gammix S70's main speeds and feeds. Here, it is configured with 2TB of capacity and claims 7,400MB/s read and 6,400MB/s write. Peak IOPS, on the other hand, are 650,000 read and 740,000 write.

Thus, sequential figures are mostly good for a PCIe 4.0 SSD. However, IOPS, and thus random access performance, lags a bit behind the theoretical best. For example, the WD Black SN850 is rated at 1M read IOPS and 710K write IOPS, while the Samsung 980 Pro is rated at 1M IOPS in both directions. Ouch.

In any case, Adata also sells a 1TB model, and both that drive and this 2TB model have Micron's 96-layer triple-level cell (TLC) V-NAND flash memory. In terms of drive endurance, the 2TB drive is capable of writing 1,480TB, which is decent performance, but not class-leading. Samsung's 980 Pro can withstand 1,200TB writes, while the 2TB Corsair Force Series MP600 is well ahead at 3,600TBW. Nevertheless, not only is Adata's 5-year warranty applicable, but with this 1,480TB worth of endurance, you can buy 810GB of write traffic every day for 5 years. This should be enough.

Digging a little deeper into the details, the Gammix S70 is powered by the InnoGrit IG5236 controller chipset. In practice, SSD controllers are black boxes whose internal workings are opaque at best to end users, at least those who do not have a master's degree in integrated circuit design with a sideline in NAND flash memory complexity.

But for the record, the InnoGrit IG5236 is a multi-core NVMe 1.4 compliant controller with eight memory channels and a quad-lane PCIe 4.0 interface. It is also manufactured on TSMC's 12nm FinFET process, which is a fairly advanced slice of silicon and favorable for efficiency and thermal management. It also supports both dynamic SLC and DRAM caches. In this implementation, Adata has up to 666 GB of SLC cache and 1 GB of DRAM cache. All in all, the InnoGrit IG5236 certainly looks competitive on paper.

It is also worth noting that Adata states that this drive will maintain a static bill of materials throughout its life. In other words, key components such as the controller and NAND flash chips will not change during the life cycle of the drive. Buyers can be confident that quality and detailed specifications will not change.

Finally, the Gammix S70 is constructed with a fairly thick and heavy heat sink. While this is a good thing with respect to heat and sustained performance, it is also ergonomically awkward. The M.2 drive is thick enough at 1.5 cm high that it may prevent the installation of a PCIe x16 slot or graphics card, depending on the exact layout of the motherboard. This is worth keeping in mind.

Given all of this, you will probably be surprised at how fast this drive really is. In raw sequential values, it rivals the best drives; at 6,950 MB/s, it is nearly as fast as any flash drive we've tested; only the Sabrent Rocket Plus exceeds it, and even then only slightly. On the other hand, even though most of the competitors were tested in the slower 1TB configuration, their 6,340 MB/sec write is still the fastest drive we have tested.

Of course, these peak values reflect drive performance in SLC cache mode. In internal file copy tests, initial performance starts at 1.8 GB/sec and drops to 1.1 GB/sec after about 600 GB of SLC cache is used up. After about 750GB of writes, performance declined further, fluctuating between 500MB/sec and 750MB/sec. This is adequate performance, but not great.

Another aspect that is "a little less impressive," as one would expect from the IOPS specs, is the random 4K performance. 66MB/sec on reads and 202MB/sec on writes at queue depth 1, which is quite a difference from offerings like the WD Black SN850, which recorded 83MB/sec and 274MB/sec, respectively.

How these results translate to actual performance, e.g., game load times, is necessarily not much: the Gammix S70 lags behind by only 0.5 seconds in the Final Fantasy XIV: Shadow Bringers level load benchmark The Gammix S70 is still a bit of a disappointment. But that could change with the arrival of Windows 11 later this year and the Direct Storage technology first used in the Xbox Series X. The only way we'd choose this SSD over the WD Black SN850 is if it was heavily discounted. That may sound like condemnation with faint praise. But the point is that this drive is good enough, and at the right price, I would gladly use it over anything else. As of this writing, it is difficult to sell the Gammix, as the price is about the same as the WD Black SN850. However, if it were a little cheaper, things would be very different.