Promise Pegasus2 M4 (4x1TB) Thunderbolt 2 DAS Review
by Kristian Vättö on September 12, 2014 9:00 AM EST- Posted in
- Storage
- Thunderbolt
- m4
- Promise
- DAS
- Thunderbolt 2
- Pegasus2
Final Words
It is clear that the Pegasus2 M4 is a niche product. Any user that does not require portability will be better served by the R4, which is a similar 4-bay Thunderbolt 2 device but with 3.5" hard drives instead of 2.5" drives. As a result it is physically larger but should provide better performance since 3.5" hard drives tend to be faster than their 2.5" siblings. We have not tested the new R4, but we did test the original R6 when it was released and the performance was better than what the M4 offers. The R4 is also more cost efficient and it retails for $1,499 at the Apple Online Store, but that includes 8TB of data so that works out to be $187.50 per terabyte whereas the M4 costs $250 per terabyte.
Furthermore, a single 3.5" external hard drive can beat the M4 in capacity while costing a fraction of the M4's price, and it provides the same or even higher level of portability. That leaves redundancy and performance as the M4's advantages. Since the M4 supports RAID 5 and RAID 6, it can withstand one or two hard drive failures without losing any user data. The performance is also much better than what you can get from single 3.5" drives, which usually max out at around 200MB/s, whereas the M4 manages over 350MB/s in RAID 5 configuration.
I did notice one irritating thing in the M4, however. The fan in the M4 makes a fairly loud noise even when the device is idling. Unfortunately I do not have a proper decibel meter to provide an objective measure of the noise, but WebPAM PRO showed the fan speed to be 2,400rpm, which certainly sounds high. I would not say the noise is too loud to distract me while working, but it is clearly distinguishable over the noise that the three desktops in my office create.
Another thing I have a slight problem with is the lack of additional capacity points. 4TB is not much for a video professional, especially if 4K video is being stored, and 1.5TB and 2TB 2.5" 9.5mm hard drives are not that expensive anymore. A 2TB 2.5" 9.5mm hard drive costs $127 online while a similar 1TB drive costs $65, so the price is exactly double. It is understandable that Promise must have high margins because these are not mainstream products that sell in high volumes and thus I can see the cost sensitivity issue with higher capacities, but a 4x2TB configuration at $1,499 would still leave Promise with a ~50% margin on the hard drives.
All in all, the M4 targets a fairly small niche. I can only think of video professionals (maybe photo and audio to some extent) that would see the value in the M4 because if you do not need portability, redundancy, and high performance, there are better options in the market. However, if you need all three (e.g. for on-set video editing), the M4 does the job.
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joystone324 - Sunday, September 14, 2014 - link
no manjohnny_boy - Monday, September 15, 2014 - link
Why on Earth couldn't they make this thing use less than 10W? Each drive uses less than a watt so that leaves 6 watts left for the controller. It could be done entirely through software off an ARM SoC running linux!repoman27 - Monday, September 15, 2014 - link
This unit ships with 2.5-inch spinning disks that draw 2.5 W each when in use and over 3 W at startup. Even with staggered startup, you're at 10 W right there. Then there's the PMC-Sierra RoC, which judging by the heat sink might draw around 5 W without counting the SDRAM and NAND, and the DSL5520 Thunderbolt 2 controller which needs 2.8 W. There's also a rather large PLD and a Parade PS181 DP to DP++ converter that need juice. Since this is a two-port design, the PSU also has to be able to provide 10 W of power to the next device in the chain.Speaking of the 10 W power budget, that also has to power an active cable, which only leaves "up to 8.5 W" for the device. Since the original Thunderbolt cables could draw over 2.4 W all by themselves, and the lowest power Thunderbolt 2 controller uses another 2.1 W, you can really only count on roughly 5 W for your device design unless you use a tethered cable.
philipma1957 - Monday, September 15, 2014 - link
I own an r-6 and it has been a beast. One of the most important features of the r-6 is the drives are bootable. I own the smaller 2.5 inch 4 drive model the j4 and it is not bootable. the j4 fan was loud and whiny it sets in a box doing nothing. It was designed to stack under a mac mini and it was very disappointing purchase for me. I would hate to buy this unit and find it is not bootable. and has the same whiny loud fan. And if I was doing video since I have to plug this into a power source I would just get an r-4 or r-6 and use that. The r-6 can have a lot of setups that are fast and back up your info.mschira - Tuesday, September 16, 2014 - link
this is silly. Why would I bother with a RAID setup for 4 TB, when I can get a 4TB single platter in 3.5"?That's gonna be smaller than 4 2.5" drives, consume less power, and on goes the list of advantages.
Yea, it's somewhat less fail tolerant because I can't use RAID 5, but it will fail much less often because it is only ONE drive rather than 4 drives.
But seriously? RAID 5 will give you 3TB. How about using two 2TB 2.5" drives in RAID 1? Will be more compact, fail less often.
Now use 2TB 2.5" drives (i.e. 12mm ones) and the situation starts to turn. You can build a 6GB RAID 5 setup with good speed fault tolerance and a reasonable size.
May not be a magic bullet in many occasions, but at least in a few situations.
Cheers
M.
RedHunter2386 - Thursday, September 18, 2014 - link
Please keep in mind that PMC is part of Promise Technology and is also known at the "OEM"-brand of Promise. Therefor it is not that strange they would use their own chip in their devices, even if the specs are higher than the unit actually demands.On the Promise booth at IBC (in Amsterdam), they were showing the Pegasus M4 with 4x 512GB Samsung 840 EVO SSDs. This was a demo unit, as there is no official SSD version available (yet). The speeds in Blackmagic Speed Test were showing around 1100MB/s Write and 1150 MB/s read. That's quite a difference from the speeds mentioned in this review.
stux - Tuesday, September 23, 2014 - link
I think this review needs an update or a ReduxFor a TB drive enclosure its absolutely imperative to test it on a Mac with TB2, or you might as well not bother, especailly with the reports for 1100/1150MB/s performance with 4x 840 Evo SSDs.
Drive noise is a very big concern with a product like this. I've seen dB meter apps for iPhones, and audio engineer friend of mine raves about one and how its with in point something something of his lab meter. Cheap, and cheerful and would help a lot with objectively quantifying the noise.
This drive sounds like its trying to compete with the Drobo Mini, which has 4 2.5" bays and an m-sata 5 bay which can act like a cache card, and is USB3 and TB
I'd really really like to see a performance comparison between the drobo mini and the the M4 with 4x 1 or 2TB HDs and also with SSDs. That would be very interesting, and very valuable to mac professionals trying to work out high performance or high capacity storage solutions for portable scenarios.
Thanks Kristian, I did enjoy the review :)
jonb8305 - Wednesday, October 15, 2014 - link
Someone should do an update with the official SSD version from Promise http://www.promise.com/promotion_page/promotion_pa...PeterBr - Sunday, May 3, 2015 - link
I just placed an order for a PROMISE Pegasus2 M4 4TB at $1500 (this is a 2.5" disk version), and now Im thinking I could have purchased a 3.5" version from another company with more TB installed for the same price. Could anyone recommend a better prices/deal and reliable 8TB or higher raid drive with thunderbolt for 4k video editing?