The MyDigitalSSD SBX SSD Review: NVMe On The Cheap

Sequential Read Performance

Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.

The burst sequential read speed of the MyDigitalSSD SBX is clearly faster than what SATA drives offer, but the Samsung drives and even the larger capacities of the Intel SSD 760p are in an entirely different league. The Phison E7 drives with planar MLC offer about the same performance as the SBX.

Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data.

The flash is clearly much more of a bottleneck than the PCIe x2 interface on the longer sequential read test, where the internal fragmentation left over from the random write test prevents the SBX from delivering data any faster than the SATA SSDs. The Intel SSD 760p performs even worse at 128GB, but beats the SBX at 512GB.

Power Efficiency in MB/s/W	Average Power in W

Power efficiency continues to be a downside to the MyDigitalSSD SBX even though its power draw in absolute terms is substantially lower than the other NVMe drives. The Intel 760p is clearly worse off this time with much lower efficiency at every capacity, while Samsung's high-end drives are fast enough to offer efficiency as good or better than SATA drives.

MyDigitalSSD SBX 512GBMyDigitalSSD SBX 128GBMyDigitalSSD SBX 256GBIntel SSD 600p 512GBIntel SSD 760p 128GBIntel SSD 760p 256GBIntel SSD 760p 512GBSamsung 960 EVO 1TBSamsung 960 EVO 250GBSamsung 960 PRO 512GBTeam T-Force Cardea 240GBPatriot Hellfire 480GBIntel SSD 545s 512GBSamsung 860 PRO 512GBCrucial MX500 500GBToshiba TR200 240GBToshiba TR200 480GB

The sequential read performance of the SBX improves a bit between QD2 and QD8, allowing it to eventually surpass the Intel 760p that is generally better at QD1 but doesn't scale up with higher queue depths.

Sequential Write Performance

Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.

The burst sequential write speed of the MyDigitalSSD SBX exceeds that of SATA SSDs, though only barely in the case of the 128GB SBX. The 128GB Intel 760p fails to keep up with mainstream SATA drives, while the larger capacities have a clear lead over the SBX.

Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.

On the longer sequential write test, only the 512GB SBX is able to stay ahead of mainstream SATA SSDs. The Intel 760p has a minimal performance lead over the SBX at 128GB, growing to a 22% advantage at 512GB.

Power Efficiency in MB/s/W	Average Power in W

The MyDitigalSSD SBX's power efficiency during sequential writes is better than Intel's drives, but not much else. The SBX is paying the power cost of PCIe (albeit only two lanes) but delivering SATA performance.

MyDigitalSSD SBX 512GBMyDigitalSSD SBX 128GBMyDigitalSSD SBX 256GBIntel SSD 600p 512GBIntel SSD 760p 128GBIntel SSD 760p 256GBIntel SSD 760p 512GBSamsung 960 EVO 1TBSamsung 960 EVO 250GBSamsung 960 PRO 512GBTeam T-Force Cardea 240GBPatriot Hellfire 480GBIntel SSD 545s 512GBSamsung 860 PRO 512GBCrucial MX500 500GBToshiba TR200 240GBToshiba TR200 480GB

The MyDigitalSSD SBX delivers essentially the same sequential write performance at all tested queue depths, and power usage is also flat. The results from the SBX are most comparable to mainstream SATA drives, while the high-end NVMe drives are generally much faster and more power hungry.