Promise Pegasus R6 Hard Drive Review

28 Sep

PROMISE Pegasus R6

The Promise Pegasus R6 ($1,999 list at the Apple store) is an extremely pricey, very large, crazy-fast external hard drive array with a Thunderbolt interface for the high-end graphics industry. If you’re a hardcore Photoshop, Premiere Pro, Final Cut Pro, or Avid Media Composer user, your mouth will start salivating after you read this. For everyone else, standard hard drives will do you fine. The Promise Pegasus R6, in short, is professional-grade equipment.

Promise Pegasus R6 Design and Features
The Pegasus R6 looks like many other multi-drive external boxes. It’s a big metal block that will take up a lot of space on your desk (about 10 by 7.25 by 9.75 inches, HWD). The R6 needs to be that big to accommodate the six full-sized 3.5-inch spinning hard drives working in sync to give you loads of fast, secure storage. The drives are all mounted on trays that both lock and slide in/out easily. These trays will be familiar to any user who uses hot swappable hard drives in a server or workstation.

Promise Pegasus R6 View SlideshowSee all (6) slides

Promise Pegasus R6 : Front
Promise Pegasus R6 : Thunderbolt
Promise Pegasus R6 : Family
Promise Pegasus R6 : Back


The drives themselves are 7,200rpm 2TB hard drives. This is kind of surprising since as a group, they outperform an internal SSD (see performance below). Conventional wisdom would expect 10,000rpm drives or SSDs in this application, since individually SSDs and 10k drives tend to have higher throughputs than 7,200rpm drives. However, working together, the six drives here are faster than any single drive. On the front of the drive, each tray has its own status light and drive access light. The power button is backlit to indicate power on, errors, or sleep mode; and just below there are a couple of Thunderbolt lights to indicate that either of the two ports are active. The back of the unit is quite Spartan. There’s just the standard power jack for a three-pronged power cable and two Thunderbolt ports. This means that you can’t downshift to FireWire or USB if you’re transferring files to a non-Thunderbolt Mac. A minor inconvenience to be sure, but still.


The two Thunderbolt ports are versatile: they pass data through, so you can daisy chain up to six Pegasus R6 (or R4) drives together. Six Pegasus R6 arrays will give you about 60 TB of data storage, connected through one Thunderbolt port. You can also plug a mini-DisplayPort monitor into the Thunderbolt port on the back of the Pegasus R6, so you can use the drive and a monitor simultaneously with only one connection. This goes double for an iMac 27-inch with two Thunderbolt ports. Theoretically, you could have 12 Pegasus R6 drives and two 24- or 27-inch Cinema displays connected to your 27-inch iMac. That’s a total three screens and 121 TB of drive space for $28,273 before tax (including twelve $49 Thunderbolt cables and a 27-inch iMac). Unfortunately, the Apple Thunderbolt cable isn’t included with the Pegasus R6 or R4.

Promise Pegasus R6 Specifications

System Type
Promise Pegasus R6 Storage Capacity (as Tested)
12000 GB
Promise Pegasus R6 Rotation Speed
7200 rpm
Promise Pegasus R6 Ports
SATA, Thunderbolt


The Pegasus R6 is set for RAID 5 out of the box, and that’s how we tested the drive. RAID 5 (striping and data parity) gives the user a lot of benefits: some speed, bulletproof data protection, and hot swap capability. (For more on the difference between RAID configurations, check out our primer on RAID, RAID Levels Explained. RAID 5 basically gives you one-drive failure protection: If one of the hard drives physically fails, the data parity files on the remaining drives allow you to keep working until you replace the bad drive. You can replace the bad drive while the unit is operating and rebuild the array on the fly, so there’s virtually no down time. The six-drive array gives you 10TB instead of the nominal 12TB as a result of the extra data parity files, but that’s still a good tradeoff. If you really need to get all the performance and drive space you can out of the Pegasus R6, you can set the RAID level to 0, but if any drive physically fails, you’ll lose all your data. (RAID 0, 6, and 10 are the available configurations).

The Pegasus R6 comes with only one piece of software on board: a controller program that can monitor the health of the RAID array and reconfigure it based on your needs. As with all RAID devices, I’d recommend backing up your data elsewhere before changing RAID configs, as the process usually entails formatting the drive. The drive is formatted HFS+, the Mac OS X native format, and as such it can be used as a Time Machine backup drive out of the box, though that would make it a very expensive 12TB backup drive. Most users will likely use the drive as a project work drive for high-end tasks: using programs like Photoshop, Premiere Pro, or Final Cut Pro/ Pro X. You could theoretically house a massive database or Website on the drive as well, but there aren’t any servers or workstations with Thunderbolt, at least until Apple updates the Mac Pro with a Thunderbolt port. The drive is not Windows compatible at this time. There are no shipping Windows PCs with the mini-DisplayPort shaped Thunderbolt port, and there are no Windows drivers for the R6 on Windows, even in Boot Camp.

Promise Pegasus R6 Performance
Here’s the reason you’re considering this drive in the first place: performance. The Pegasus R6 using the Thunderbolt interface is fast. Unbelievably fast. It’s so fast that it beats the internal solid-state drive (SSD) in an Apple MacBook Pro in speed and throughput tests. We used our standard drag-and-drop test of a 1.2 GB folder, and the Pegasus R6 took six seconds! Compare that to the Editors’ Choice winning 1TB Iomega eGo Blackbelt ($199.99 list, 4 stars) which took at 35 seconds under USB 2.0 and 22 seconds with FireWire 800. The desktop-class Iomega eGo Desktop Hard Drive, Mac Edition (2TB) ($185 street, 3.5 stars) (16 seconds) and Western Digital My Book Studio Edition II ($429.99 list, 4.5 stars) (32 seconds) were both slower using FireWire 800. The Pegasus R6 is even faster than the Apricorn Mac Array ($1399 list, 3 stars), which is a four-SSD internal RAID 0 array meant to be installed in Mac Pro towers (10 seconds). Until this point, the Apricorn MacArray was the fastest “drive” that we’ve tested. That means that multi-Gigabyte file transfers will take seconds instead of minutes (or instead of hours under USB 2.0). That alone will make you more productive.

PROMISE Pegasus R6

We also ran the drive through a couple other tests to show throughput numbers. The AJA System test shows throughput numbers in a quick read/write test to see how the drive would do in a video-editing situation. Using a setting for a 512MB 1080p (10-bit) HD video file, the drive was about to write at about 620 Megabytes per second and write at about 480 MBps. The internal SSD in the MacBook Pro was only capable of 185MBps write and 197 MBps read. Contrast this with a FireWire 800 drive at about 48 MBps write and 46MBps read. Using the Pegasus R6 will mean a lot less time waiting for HD video files to simply transfer from your camera to the drive to your Mac. USB 2.0 would be in the region of 21 MBps.

PROMISE Pegasus R6

The Pegasus R6 is about 16 to 19 cents per GB (depending on RAID level), so it has a distinct price premium on a dollar per GB basis versus smaller drives like the Iomega eGo Desktop drive, Mac Edition (9 cents per GB). However, the speed and reliability difference is way worth it, especially if you’re using the drive on multi-million dollar projects that have to be done yesterday. You can get similar storage space by buying multiple drives like the Western Digital My Book Studio II (two 6TB drives at $550 each would do it), but the WD drives won’t get you the performance you crave. Essentially, if you can justify writing the Pegasus R6 off on a tax return, capital budget, or business expense sheet, it’s worth buying one.

Basically, you want to buy a Promise Pegasus R6 if your performance has been drive-limited in the past (just about all performance tasks, but especially high-end video and photo production). It’s the fastest drive and interface combo out there, and it has the benefit of being the first on the market. There will likely be faster and less expensive Thunderbolt drives in the future, but if you’re itching for a fast drive to go along with your new quad-core iMac or MacBook Pro, and don’t mind paying a steep premium, the Promise Pegasus R6 is worth serious consideration.


Promise Pegasus R6

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Posted by on September 28, 2011 in Uncategorized


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