2TB Class Performance Testing
Even with all of the talk about SSDs getting larger, there are still very few 2TB M.2 models available today. Most fall into two camps, those based on the Phison E12 like the BPX Pro we're testing today and those based on the Silicon Motion, Inc. SM2262EN like the HP EX950 in the charts.
Samsung promised a 970 EVO Plus in this capacity, but we've yet to see it for sale. There are a few older models like the 960 EVO and 960 Pro in 2TB. The 970 series only saw the EVO model with a 2TB capacity.
Sequential Read Performance
Every drive we've tested with the Phison E12 controller (and Intel's in-house controller as well) shows a strong dip at queue depth (QD) 2 that carries over to QD4. This is just a hang up with our testing algorithm and not an issue with the drive's real-world performance.
In other software, even with this same software but in a different order, the issue goes away. For the most part, all of the modern generation premium NVMe SSDs with 8-channel controllers reach the highest throughput available with a PCIe 3.0 x4-lane interface.
Sequential Write Performance
We want to look more at other areas of performance with these drives. The sequential write performance is one area where we still see some differences between products. The 2TB BPX Pro starts strong with a very high QD1 write burst over 2,000 MB/s. The drives scales well to QD2 where it reaches peak throughput at nearly 2,800 MB/s.
Sustained Sequential Write Performance
With a single 128KB write to the entire user area of the drive, we get a chance to see how the SLC cache performs and where the performance drops off. The 2TB BPX Pro comes out of a low power state mode and quickly jumps to roughly 2,200 MB/s for around 20% of the user capacity.
Our sample drive entered a period where the performance fell flat for a few seconds and then recovered. We haven't seen this on any of the other BPX Pro, or E12 drives we tested with firmware 12.1.
Random Read Performance
The E12 with Toshiba 64L BiCS Flash doesn't have the same explosive responsiveness as drives with Micron's 64L TLC. They do cost significantly less through than drives like the ADATA SX8200 Pro and HP EX950.
Random Write Performance
The 2TB BPX Pro does have very strong random write performance at low queue depths. As we ramp up the workload the drive falls short of the other 2TB drives in our charts, but by that time we're well outside of the consumer workload range.
70% Read Sequential Performance
The Phison E12 uses a powerful 2-core processor with a coprocessor that allows these drives to blaze through mixed workloads. The BPX Pro is one of the best drives available for sequential mixed workloads as long as you don't push the workload past the SLC buffer.
70% Read Random Performance
Even with the powerful processor, the slower bus interface on the Toshiba 64L flash stifles the random mixed workload performance on the 2TB BPX Pro. The drive is still much quicker than many SATA and NVMe SSDs shipping today, but can't compete one to one with those using Micron 64L TLC.