Slightly wider and deeper than a Mac mini, the Promise Pegasus J4 2TB RAID has space for four 2.5-inch drives.

Our review unit was fitted with 500GB Toshiba drives, configured as a striped RAID array for speed. A driver has to be installed before OS X will recognise the storage.

The array can be re-configured – and its contents destroyed – using Disk Utility. As a mirrored array, the capacity is quartered, the speed reduced, but protection is added against up to three of the disks failing.

In its speedy striped state, transfer rates maxed out at 482.4MB/second and 538.5MB/second for sequential read and write operations. The average read and write speeds were significantly lower at 330.3MB/ second and 373.6MB/second.

BlackMagic’s Disk Speed Test determined these rates to be suitable for working with video of 10-bit colour depth at up to 1080p and 2K at 25 frames per second.

Like many Thunderbolt drives, you’ll need to provide a data cable. Apple now sells a half-metre version for £25, and has reduced the two-metre version to £35.

The drive emits a faint hum that will be drowned out in a busy environment, but be sure to get a longer cable to keep the flashing drive activity LEDs out of immediate sight.