OWC Mercury Elite Pro Dock: Speed vs Transfer Size

OWC Mercury Elite Pro Dock

Configurations up to 32TB (2 X 16TB). MPG tested the 24TB model incorporating dual Toshiba 12TB MG07ACA12TE drives which are very high performance hard drives.

This page evaluates speed versus I/O transfer size of the OWC Mercury Elite Pro Dock.

CLICK TO VIEW: OWC Mercury Elite Pro Dock Capacities

Test results: speed vs transfer size

Test mule was the 2019 iMac 5K. The run-sequential-suite command of diglloydTools Disktester was used.

disktester run-sequential-suite --iterations 5 --test-size 4GB

Speed always varies with transfer size, whether on hard drives or SSDs. There is always overhead e.g., writing 1MB as thirty-two 32K transfers is far less efficient than writing 1MB as a single transfer). With RAID-0 and RAID-5, the striping aspect means that the transfer is split into blocks across drives, the “stripe size” being the determinant of how the transfer is split up.

The fast Toshiba hard drives in the OWC Mercury Elite Pro deliver outstanding performance with small transfer sizes, probably due to the very large on-drive caches.

Wow! Both read and write transfer speeds rival the speeds of most SSDs for 32/64/128K transfers and are almost as good with large transfers as SATA SSDs—impressive!

Vertical scale is MB/sec. Horizontal scale shows transfer size. RAID-0 used 64K stripe size; RAID-5 uses 16K stripe size (default, not configurable).

OWC Mercury Elite Pro Dock: speed vs transfer size (RAID-0 mode)