The MyDigitalSSD SBX SSD Review: NVMe On The Cheap

Conclusion

The MyDigitalSSD SBX sits at the bottom of the NVMe SSD market, with prices that have closed the gap between SATA and NVMe SSDs. The SBX isn't quite cheap enough to be competing head-to-head against mainstream SATA SSDs, so the SBX still needs to offer compelling advantages over those SATA drives. Against other NVMe SSDs, the SBX seldom comes out ahead on performance comparisons, but it has the advantage of significantly lower prices and power consumption.

The main selling point for the SBX over SATA drives is performance. Mid-range and high-end SATA drives offer nearly identical real-world performance thanks to the limitations of the SATA interface. The PCIe x2 interface used by the MyDigitalSSD SBX is half as wide as that used by most NVMe SSDs, but still gives the SBX plenty of room to outperform SATA SSDs. The SBX doesn't always use all of that interface bandwidth, but it does manage to deliver real-world performance that exceeds SATA SSDs. For most users looking to step up from a mainstream SATA drive, the added performance the SBX brings will be much more useful than the added endurance of a similarly-priced premium MLC-based SATA SSD.

Because the MyDigitalSSD SBX is a low-end drive (within its NVMe market), it makes some sacrifices compared to most NVMe SSDs. The SBX is clearly optimized for peak performance on common client/consumer workloads. When subjected to particularly harsh workloads or the difficult operating conditions of a nearly-full drive, the performance of the SBX drops substantially. Previous budget-oriented SSDs like the Intel SSD 600p and the first-generation WD Black SSD have been similarly afflicted, but unlike those drives the MyDigitalSSD SBX manages to keep its performance at or above the level of mainstream SATA SSDs even on our harder tests.

With an emphasis on low price, it's no surprise to see the SBX product line including smaller capacities that many high-end NVMe SSDs have dropped. The MyDigitalSSD SBX is not able to avoid the performance hit that especially small SSDs suffer as a result of having fewer NAND flash devices to use in parallel. The 128GB SBX performs very differently from the 512GB SBX, but each is still a step up from SATA drives of similar capacity. The smallest capacities of the SBX also don't seem to be as acutely limited as the smallest Intel SSD 760p drives, which tend to offer better worst-case performance than the SBX at the cost of lower peak performance for common workloads.

Aside from pricing, the most significant and consistent disadvantage NVMe drives have compared to SATA drives is with power consumption: efficiency needs to be sacrificed in order to deliver the highest performance. The MyDigitalSSD SBX is without question the lowest-power NVMe SSD we have tested, but its low performance means that it doesn't provide any real improvements to power efficiency. The low power draw of the SBX means that it is no more susceptible to overheating than SATA drives, but the SBX won't give you the same battery life that a good SATA drive will.

This is especially true when taking into account the difficulties with NVMe power management. Phison-based drives are far from the only NVMe SSDs that have severe power management issues, but the earlier Phison E7 controller platform produced some of the most embarrassing power management quirks we've seen. The Phison E8 controller used by the SBX is a clear improvement, but the firmware still needs work. As tested and currently shipping, the SBX cannot use its deepest idle power state and cannot stay in its intermediate sleep state for more than a few seconds without waking back up. The MyDigitalSSD SBX is a poor choice for battery-powered systems, but this may be fixable with a firmware update.

ADATA is one of the only brands offering NVMe SSDs at anything close to the pricing of the MyDigitalSSD SBX. Their SX6000 is a bit cheaper than the SBX but uses a Realtek SSD controller. Realtek is relatively new to the SSD controller space and we have never tested one of their drives, so we cannot say much about its performance. The ADATA SX7000 uses the Silicon Motion SM2260 controller and first-generation Micron 32L 3D TLC, which make it similar to the Intel SSD 600p in design and performance. The MyDigitalSSD beats the ADATA SX7000 on performance and usually on price as well.

Above the SBX on the price scale are drives that are truly high-end, with much higher benchmark performance results but only marginally better real-world performance. These drives should only be considered by consumers with heavy storage workloads, those who need a NVMe SSD with better power management for a notebook, or those who simply want bragging rights.

The value proposition of mainstream SATA SSDs is still hard to argue against, especially as prices are finally in decline. For all that it may be low-end by NVMe standards, the MyDigitalSSD is still a more premium product than something like the Crucial MX500, and the SBX requires you to pay at least 20% more per GB for its added performance. NVMe drives are getting more affordable, but they aren't for everybody yet.