IT Pro is supported by its audience. When you purchase through links on our site, we may earn an affiliate commission. Learn more

Promise Pegasus R6 review

The first Thunderbolt storage array is finally here and it blitzes through our benchmarks at astonishing speeds.

When the Pegasus was configured using a RAID level with more data redundancy, large files performance was generally a bit slower while small files performance was a bit quicker.

The RAID 0 performance of the Pegasus Promise R6 when fitted with six 1TB 7,200rpm hard disks.

The Promise Pegasus R6 is incredibly fast when configured as a RAID 0 array.

To see how much of this incredible performance was due to RAID rather than the Thunderbolt interface, we also tested the Promise R6 with just a single disk fitted. In this configuration large files were written at 176MB/s and read at 122MB/s. Small files were written at 169MB/s and read at 109MB/s. Even without the benefit of RAID, a Thunderbolt-connected disk is still clearly, if not so dramatically faster, than the alternatives. USB3 disks, for example, can reach 100-120MB/s when writing large files.

The performance of the Pegasus Promise R6 when fitted with a single 1TB 7,200rpm hard disk.

The Promise Pegasus R6 isn't as awe-inspiringly fast when fitted with just a single disk, but it's still fast.

Although the Pegasus R6 isn't available diskless or pre-fitted with solid state disks (SSDs), we wanted to see how just fast it could copy files when fitted with SSDs. We installed a pair of 240GB Kingston HyperX SSDs configured as a RAID 0 array. Although it was faster than a hard disk configuration in almost all of our tests, it wasn't dramatically quicker. Large files were written at 576MB/s and read at 596MB/s. Small files were written and read at around 208MB/s. The hard disk configurations did have the benefit of six disks though, where as our SSD configuration used just two SSDs. In any case we can't imagine too many SSD Thunderbolt arrays in actual use, if only because of the added expense on what is already a very pricy array.

The RAID 0 performance of the Pegasus Promise R6 when fitted with two Kingston 240GB HyperX SSDs.

The Promise Pegasus R6 is fast when fitted with a pair of Kingston HyperX 240GB SSDs, although not as breathtakingly quick as we were expecting.

So what's our verdict?


There's no doubt that thanks to Thunderbolt, the Promise Pegasus R6 is one of the fastest storage products we have ever seen. It's also very expensive, although its price per gigabyte of 18p, while high, isn't outrageously extortionate. However, even if you have the modern Macs required to use it, you'll need to transfer and manipulate seriously massive amounts of data regularly, such as HD or 4k video files or sprawling databases, to justify its high price.

SPECIFICATIONS Chassis: Desktop Storage: 6 x 3.5in 1TB 7,200rpm SATA2 hard disks in removable disk trays (not hot swappable) Array support: RAID 0, 1, 5, 6, 10 Network: 2 x Thundebolt Other ports: 1 x serial port Management: Promise Utility 3.16 Price per gigabyte: 18p Power consumption Idle 42W Active 50W BENCHMARKS RAID 0 Large write 590MB/s Large read 499MB/s Large average 545MB/s Small write 196.9MB/s Small read 104MB/s Small average 150.5MB/s RAID 5 Large write 482MB/s Large read 374MB/s Large average 428MB/s Small write 220MB/s Small read 111MB/s Small average 165.5MB/s RAID 6 Large write 494MB/s Large read 250MB/s Large average 372MB/s Small write 185MB/s Small read 113MB/s Small average 149MB/s RAID 10 Large write 344MB/s Large read 228MB/s Large average 286MB/s Small write 141MB/s Small read 148MB/s Small average 144.5MB/s SINGLE DISK Large write 176MB/s Large read 122MB/s Large average 149MB/s Small write 169MB/s Small read 109MB/s Small average 139MB/s RAID 0 SSD Large write 576MB/s Large read 596MB/s Large average 586MB/s Small write 209MB/s Small read 208MB/s Small average 208.5MB/s

Featured Resources

ZTNA vs on-premises VPN

How ZTNA wins the network security game

Free Download

The global use of collaboration solutions in hybrid working environments

How companies manage security risks

Free Download

How to build a cyber-resilient business ready to innovate and thrive

Outperform your peers in your successful business outcomes

Free Download

Accelerating your IT transformation

How Cloudflare is innovating for CIOs to start 2023

Watch now

Most Popular

Tech pioneers call for six-month pause of "out-of-control" AI development
artificial intelligence (AI)

Tech pioneers call for six-month pause of "out-of-control" AI development

29 Mar 2023
Getting the best value from your remote support software
Advertisement Feature

Getting the best value from your remote support software

13 Mar 2023
3CX CEO confirms supply chain malware attack

3CX CEO confirms supply chain malware attack

30 Mar 2023