USB 3.2 Gen 2x2 State of the Ecosystem Review: Where Does 20Gbps USB Stand in 2020?

Synthetic Benchmarks - ATTO and CrystalDiskMark

Western Digital claims claims read and write speeds of up to 2000 MBps for both the P50 and the Extreme PRO Portable SSD v2, and these are backed up by the ATTO benchmarks provided below. Unfortunately, these access traces are not very common in real-life scenarios.

Drive Performance Benchmarks - ATTO

SanDisk Extreme PRO Portable SSD v2 2TB [ASM3242]Western Digital WD_BLACK P50 1TB [ASM3242]SanDisk Extreme PRO Portable SSD v2 2TB [ASM3242 via JHL6540]SanDisk Extreme PRO Portable SSD v2 2TB [JHL6540]SanDisk Extreme Portable SSD v2 1TB [ASM3242 Skylake]SanDisk Extreme Portable SSD v2 1TB [ASM3242 via JHL6540]SanDisk Extreme Portable SSD v2 1TB [ASM3242]SanDisk Extreme Portable SSD v2 1TB [JHL6540]Western Digital WD_BLACK P50 1TB [ASM3242 via JHL6540]Western Digital WD_BLACK P50 1TB [JHL6540]Expand All

On the Haswell testbed, the Extreme PRO v2 hits 1.94 GBps writes, while the P50 manages 1.92 GBps. When connected using the eGFX enclosure to the Thunderbolt 3 port of the Hades Canyon NUC, the writes suffer a significant drop to the 1.4 - 1.5 GBps range, while the drop in the reads is not as drastic - ending up around 1.8 GBps for both of the drives.

CrystalDiskMark, despite being a canned benchmark, provides a better estimate of the performance range with a selected set of numbers. As evident from the screenshot below, the performance can dip to as low as 33 MBps for low-queue depth 4K random reads.

Drive Performance Benchmarks - CrystalDiskMark

SanDisk Extreme PRO Portable SSD v2 2TB [ASM3242]Western Digital WD_BLACK P50 1TB [ASM3242]SanDisk Extreme PRO Portable SSD v2 2TB [ASM3242 via JHL6540]SanDisk Extreme PRO Portable SSD v2 2TB [JHL6540]SanDisk Extreme Portable SSD v2 1TB [ASM3242 Skylake]SanDisk Extreme Portable SSD v2 1TB [ASM3242 via JHL6540]SanDisk Extreme Portable SSD v2 1TB [ASM3242]SanDisk Extreme Portable SSD v2 1TB [JHL6540]Western Digital WD_BLACK P50 1TB [ASM3242 via JHL6540]Western Digital WD_BLACK P50 1TB [JHL6540]Expand All

The sequential reads and writes are more useful from a direct-attached storage viewpoint. Here, we see around 2080 MBps for the Extreme PRO v2, and 2045 MBps for the WD_BLACK P50 as the best-case performance using the Haswell testbed.