• 5.0 out of 5 stars

    Long Term Review

    I've had my unit now for around 9 months+ and here's my experience so far. Initially I was using it with the supplied 1Tb standard hard drives and it was fine but for me, I wanted more speed. Out of the box you can expect around 450-500Mb/s read and write performance which is plenty fast for most people. I decided that because I was using it with a large Lightroom library as well as editing 4K video in Final Cut Pro X that I'd see how 4 1Tb SSD's went. 2 months down the line with 4 x Samsung 850 EVO 1Tb drives I'm in performance heaven. I get over 800Mb/s write and and over 1000Mb/s reads on the device now.

    I should also point out that the unit is tiny and takes up about the desk space of an iPad Mini and is almost silent in use. The noise is a BIG issue when using standard 3.5" drive RAID units so doing Video work and having an almost silent RAID that can easily be moved between home and office with those kinds of speeds if a massive benefit for me. At the time I'm writing this review 1Tb SSD's are around £240 so you need to budget almost £2K for the Promise and SSDs but if speed, noise and portability are important to you, it's well worth the investment.

    In summary, out of the box or upgraded with SSDs this is a fantastic device. No power brick to carry around as the power supply is internal and it runs like a dream with zero hassle. Currently running on El Capitan but also used heavily on Yosemite with zero issues too.

    9 of 9 people found this useful

  • 5.0 out of 5 stars

    Wonderful Performance

    I purchased two of these units and daisy chained them to occupy only one Thunderbolt connection on my iMac. Disturbed by my four G-Drives dismounting for no logical reason and frequently during an operational day, I replaced the G-Drives with the Pegasus2 M4s. It took several hours for the new drives to synchronize but that was to be expected. Moved all my data from the G-Drives to the Pegasus and saw a significant increase in access times. The G-Drives have been retired and I will now rely on these significantly faster Pegasus drives to insure my data is secure. I kept the factory default settings and now feel comfortable that with the ability to do a hot replacement of any drive failures, the RAID configuration will serve my needs quite well. I would absolutely recommend these drives for anyone with sensitive data that they do not want to risk losing and that need to have a reliable connection without the risk of constant dismounting.

    33 of 33 people found this useful

  • 5.0 out of 5 stars


    I bought one of these and replaced all of the drives with Samsung 840 1TB SSD's. It's not a supported configuration, but it's the fastest storage I've ever seen on a mac, even in raid5. The performance in application is actually faster than the blackmagic speed test measures. Way over 1GB/sec. Reads peak out at over 1.5GB/sec. Just what I needed. If your work is dependent on IO performance this is a great way to go.

    42 of 43 people found this useful

  • 5.0 out of 5 stars

    Compact, quiet, and fast

    First impression: It is very compact, barely audible, and worked fine out of the box. It's tidy too - the power supply is internal. Speed improves after several hours when the RIAD 5 setup has completed - this happens in the background without any action required. Even during this 'slow' phase, Black Magic Disk Speed reported 321MB/s write and 312MB/s read. (Connected to a Mac Book Pro retina 15 inch 2012.)

    That was just playing... I bought the unit to be my main data drive for a Mac Pro 2013. Replacing the little HDDs with 4x Samsung Evo 1T SSDs transformed the performance. In RAID 0 the unit achieved 1095MB/s write, 1134 read. I then rebuilt to RAID 5 (which is incredibly easy with the pegasus utility); write performance dropped to 'only' 815MB/s while read speed stayed about the same at 1132MB/s. I'll keep it in RAID 5 as this is fantastic performance for a fault-tollerant disk. It is very close to silent with SSDs installed - very little fan noise.

    I would have preferred that the M4 came without disks, but apart from that this is a remarkable product.

    2 of 2 people found this useful

  • 5.0 out of 5 stars

    PROMISE Pegasus2 M4 4TB Thunderbolt 2 RAID System

    Just bought it yesterday. It's surprisingly compact and quiet. Out of the box it was simple to connect and worked exactly as advertised. Formatted automatically for RAID 5 to 3TB's of storage. That process took some time but was expected. MacPro recognized it immediately and configured it. Now that its formatted and operating, it's really fast accessing data... almost instantaneous. So far, quite pleased. As an aside, as the price of SSD's comes down, will eventually replace the mechanical drives with SSD's but right now couldn't be happier.

    55 of 57 people found this useful