OWC Envoy Pro EX SSD: Speed Across Capacity

OWC Envoy Pro EX Thunderbolt 3
OWC Envoy Pro EX USB-C

MPG tested the 4TB OWC Envoy Pro EX Thunderbolt 3 and the 4TB OWC Envoy Pro EX USB-C. Capacities available from 240GB to 4TB for both models.

This page evaluates sustained speed for large transfers across the entire volume capacity for the OWC Envoy Pro EX Thunderbolt 3 vs the OWC Envoy Pro EX USB-C model, both 4TB capacity.

Test results: speed across capacity

Test mule was the 2019 iMac 5K. The fill-volume command of diglloydTools Disktester was used. Ambient temperature 84°F.

disktester fill-volume

The fill-volume command writes the entire capacity of the volume, then reads it back. The resulting graph is excellent for seeing the true sustained performance as well as showing any variation or glitches, for either SSD or hard drives.

The OWC Envoy Pro EX Thunderbolt 3 model is a far higher performer than the USB-C model for reads, pegging-out near the Thunderbolt 3 bus limits of 2.76 GB/sec. Writes are not nearly as fast as reads, but are 47% faster than the USB-C model (for very large transfers).

The USB-C model appears to be throttled by the limits of the USB-C bus, pegging out both writes and reads at 975 MB/sec and 969 MB/sec respectively. The total bandwidth of the USB-C bus is 10 megabits per second, which in theory should be 1.25 MB/sec. However, usable bandwidth does not take into account bus overhead or parity. True usable bandwidth of USB-C appears to be about 1028 MB/sec as per the speed vs capacity findings. MPG has never tested a USB-C SSD that can exceed the speeds shown here; this is as good as it gets for USB-C.

        USB-C: 1022 write 1016 read MB/sec
Thunderbolt 3: 1435 write 2601 read MB/sec

Vertical axis MB/sec. Horizontal axis shows % of volume capacity, e.g., 50% of 4TB volume is 2TB into capacity.

OWC Envoy Pro EX Thunderbolt 3 and USB-C versions: speed across volume capacity