Final Words & Conclusion
Final Words & Conclusion
The market has seen little change in the two dominant SSD form factors, 2.5" and the M.2 2280 format reigning supreme. However, the emergence of compact gaming consoles like the Steam Deck and ROG Ally has necessitated a shift towards smaller form factors. These consoles require the use of M.2 2230 SSDs, measuring a mere 22 mm in width and 30 mm in length, to accommodate their compact designs. To meet the specific requirements of the Steam Deck and ROG Ally consoles, the Addlink S91 SSD has been meticulously designed. For detailed installation instructions, their website provides comprehensive guidance for integrating this drive into these devices. Under the hood, the S91 SSD boasts a Phison E21 controller, paired with advanced 176-layer 3D QLC NAND flash memory. Owing to space limitations, the inclusion of a separate DRAM cache chip is omitted. Instead, the S91 leverages the host system's memory (HMB or Host-Memory-Buffer), which possesses a capacity of 64 MB. It is important to note that the impressive 2TB storage capacity on a single QLC IC is notable, but it may impact performance when subjected to heavy workloads. During the engineering of the Addlink S91 SSD, the focus was on enhancing load speeds and improving workflow efficiency for gamers. While it may not claim the top spot for speed among SSDs, it offers a competitive balance between price and overall performance.
Endurance
We've talked about endurance previously; it's the number of times NAND cells can be written before they begin to malfunction. It is sufficient to remark that the values for QLC written (4 bits saved in a single NAND cell) are not particularly good at it. On this point, however, I always like to paraphrase Einstein: "Relativity, my man," he said. You can improve endurance by increasing the volume of your training sessions. 98 percent of your data is stored in a 'cold' state on your SSD and does nothing, and it is only the 2 percent of data that is written that is important. Volume sizes that are larger result in more NAND cells, and more NAND cells result in greater endurance. The S91 uses WLC written NAND and the 2TB model has a proper 450 TB written capacity for endurance. Now, if a NAND cell fails, it does not necessarily indicate that your data is lost. Many algorithms are constantly monitoring and managing your data; for example, if a cell's lifetime is about to expire, the bits inside that cell will be relocated to a more healthy cell. So how long does a 450 TWB storage unit last before NAND flash cells go the way of the dodo? Well, if you are a really extreme user, you might be writing 50 GB per day (really, normal users probably won't even write that per week), but based on that value, 50GB x 365days= 18.25 TB per year written. You get (for this 2TB model) almost 25 years of usage and half that for the 1 TB SSD version. Let me make it very clear, 50 GB per day each day of the year is a very ambitious number.
Performance
By today's standards the S91 still offers impressive performance. However, it is crucial to consider the influence of synthetic benchmarks on the overall performance assessment. Real-world trace tests indicate that the performance gap compared to competitors is relatively small. Despite being slower than other competing PCIe M.2 drives in our test group, the small form factor should be taken into account. The comparison drives we used are all full-size desktop drives.
Like other modern SSDs, the Addlink S91 incorporates a pseudo-SLC cache, which efficiently handles incoming writes but consumes four times the storage space. Our testing reveals that the SLC cache size is almost 25% of the 2TB, al; most 450-500GB, enabling the drive to primarily operate in SLC mode until it reaches capacity. This is advantageous as it allows the drive to handle write bursts, such as game installations. However, once the SLC cache is full, write speeds drop significantly to a mere 100-200 MB/s due to the slower nature of writing to QLC. Addlink's S91 is not considered a top-of-the-line SSDs they deliver fair read and write speeds of 4-5 GB/s. Our trace testing results demonstrate commendable figures, particularly in random 4K IOPS, which exhibit exceptional performance across various queues. The linear performance is also consistent, with the SSD maintaining a steady linear write speed of approximately 3750 MB/sec for continuous write up to 450 GB, making it more than capable of handling gaming PC workloads.
In scenarios involving heavy workloads, the utilization of a heatsink becomes imperative for the M.2 2230 SSD. Owing to its compact form factor and absence of an integrated heatsink, this drive tends to encounter rapid thermal throttling under full load. In my assessment, I observed thermal throttling manifesting within 20 seconds, despite an impressive data volume of ~65GB being written, which is approximately equivalent to the size of an entire game.
Concluding
The Addlink S91 2 TB SSD is currently priced at $190, which may be considered steep compared to desktop SSDs available for less than $130. However, the small-form-factor nature of this drive is a contributing factor to its premium pricing. It is worth noting that there are only a few storage alternatives available that can accommodate devices such as the Steam Deck and ROG Ally while offering a 2 TB capacity, which justifies the higher price. The Addlink S91 2 TB SSD utilizes the same components found in the Corsair MP600 Core XT, a comparable product that retails for $100. This doubling in price is significant and attributed to the unique form factor and specialized features of the Addlink S91. The Addlink S91 2 TB SSD is compatible with Gen4 motherboards, however make sure your motherboard can handle this form factor. In terms of performance, the Addlink S91 2 TB SSD falls between top-tier PCIe Gen3 and really fair Gen4 drive perf. Its specific performance varies depending on factors such as workload. When cooled, the Addlink S91 2 TB SSD demonstrates consistent peak sequential performance, with CrystalDiskMark write speeds exceeding the 4000 MB/s range and read speeds surpassing 5000 MB/s. It is important to mention that the small queue depth 4K random numbers show slightly more modest results. Overall, the SSD performs exceptionally well under most conditions and achieves high-end-class NVMe performance in specific workloads. The Addlink S91 2 TB SSD is backed by a five-year warranty or until the drive reaches its specified Total Bytes Written (450 TBW for 2TB model) value, whichever comes first. The drive is available in three capacities: 500GB, 1TB, and 2TB. While the Addlink S91 2 TB SSD is an impressive storage solution, it does have certain limitations associated with its small form factor and the use of QLC flash memory, such as the write hole and heat issues. Users should be aware that during heavy file writes when the pSLC cache is fully utilized, there may be a slight decline in performance. However, this minor reduction is unlikely to be noticeable to most users. Users seeking a high-performance storage solution on a very small form factor interface will find the Addlink S91 2 TB SSD to be a valuable investment though it is pricey. But hey, cramming this much performance ut of something so small, nice.
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