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Dual Bay Notebook Drive Enclosures
for the 2011 MacBook Pro
Originally posted Friday, December 30th, 2011, by rob-ART morgan, mad scientist
A little less than a year ago, we did a shootout between various dual bay notebook enclosures. Since then some new products have appeared including a Thunderbolt dual bay notebook enclosure from LaCie. We decided to do another shootout to see how much the new crop exceeds the 200MB/s barrier we encountered.
Using the fastest 6Gb/s solid state drives (SSDs) we sought to test the limits of 6Gb/s eSATA and Thunderbolt interfaces. We included setups with HDDs and Hybrid drives for perspective. Some dual bay enclosures require the two drives to share a single I/O port. Some enclosures dedicated a port for each drive. So here's what we observed:
LEGEND of GRAPHs (LONGEST bar means fastest)
SwiftS*2 PegT = two TransIntl synchronous SwiftDATA 6Gb/s 240G SSDs in Promise Pegasus R4 (RAID 0)
SwiftS*2 LBDt = two TransIntl synchronous SwiftDATA 6Gb/s 240G SSDs in LaCie LBD Thunderbolt (RAID 0)
SwiftS*2 miniS = two TransIntl synchronous SwiftDATA 6Gb/s 240G SSDs in Firmtek miniSwap connected to FirmTek SeriTek/6G eSATA ExpressCard
SwiftS*2 Fusion = two TransIntl synchronous SwiftDATA 6Gb/s 240G SSDs in Sonnet Fusion F2 connected to FirmTek SeriTek/6G eSATA ExpressCard
ExtPro*2 ProMin = two OWC Mercury Extreme Pro 6Gb/s 240G SSDs in OWC dual bay 3Gb/s Pro Mini connected to FirmTek SeriTek/6G eSATA ExpressCard
SwiftS*2 TTduo = two TransIntl synchronous SwiftDATA 6Gb/s 240G SSDs in CRU-DataPort ToughTech Duo connected to FirmTek SeriTek/6G eSATA ExpressCard
Conti*2 miniS = two Seagate 500G Constellation.2 enterprise HDDs in FirmTek miniSwap connected to the FirmTek SeriTek/6G eSATA ExpressCard
HybG2*2 miniS = two Seagate 750G Solid State Hybrid HDDs in Firmtek miniSwap connected to FirmTek SeriTek/6G eSATA ExpressCard
Sam*2 VRmini = two Samsung 1TB 5400rpm HDDs in CalDigit VRmini connected to FirmTek SeriTek/6G eSATA ExpressCard
"Test Mule" was a 'late 2011' MacBook Pro 2.5GHz Quad-Core i7 (17" model with ExpressCard/34 slot)
Thunderbolt is the fastest option for Apple laptops.
Seekers of fast external storage on the MacBook Pro have been frustrated in the past with only FireWire and USB 2.0 ports. Even those models with ExpressCard slots have limited bandwidth as you can see from the write speeds in the graphs. Thanks to Thunderbolt, the external enclosure transfer speeds of dual bay RAID 0 setups have more than doubled.
Dual port eSATA notebook enclosures are fast, but bandwidth limited with ExpressCard.
The fastest dual bay eSATA enclosures had two eSATA ports -- one for each drive. That produced read speeds significantly faster than the dual bay enclosures with a single eSATA port. However, the write speeds were about the same for both. Because eSATA ExpressCards are bandwidth challenged and are only available on 17" MacBook Pros, the ExpressCard slot might be headed for extinction. However, the dual bay, dual port eSATA enclosures will continue to be a viable option for the Mac Pros with SATA/SAS host adapters.
The Hybrid Solid State HDDs are not a panacea.
I can tell from your emails that many of you are hopeful that Seagate's 6Gb/s Solid State Hybrid HDDs with reasonable cost and higher capacities will bridge the gap between "normal" HDDs and expensive, capacity limited "pure" Solid State Drives (SSDs). Our testing indicates that they are slightly better than the fastest HDDs but can't hold a candle to SSDs. Finally the Hybrid HDD was susceptible to a bug in the current build of OS X Lion that caused it to hang the system and require a forced power down. (Hopefully that will be fixed soon.)
The 6Gb/s SSDs are faster than all interface options.
Though we used 6Gb/s SSDs in our testing (to squeeze every last drop of speed), the 3Gb/s SSDs will produce similar results in most dual bay enclosures connected to the Apple laptops. And in the case of enclosures with single eSATA ports, the HDDs came very close to the SSDs in large sequential transfer speed. The biggest advantage in choosing SSDs for your Apple laptop's external storage is exhibited when doing small random transfers. They also trounce the HDDs in seek time and number of transactions per second.
Synchronous SSDs are 80% faster than asynchronous SSDs in the real world.
You may have noticed that there are different models of SSD. One difference is that the lower priced "consumer" models use asynchronous flash NAND while the higher priced "enterprise" or "pro" models use synchronous flash NAND. At first we saw little difference in performance as illustrated by the QuickBench graph below. But when we ran our Finder Duplicate test, it was clear that the SSDs with synchronous NAND were faster -- up to 80% faster. (For more on "synchronous vs asynchronous flash NAND," see the article on HardOCP.
NOTE: In these graphs, we used a Mac Pro with the HighPoint RocketRAID 2744 to measure the maximum performance of the async and sync SSDs. The FirmTek miniSwap enclosure with dual eSATA ports housed the drives.
LEGEND of GRAPHs (LONGEST bar means fastest)
SwiftSync*2 = two TransIntl SwiftDATA 6Gb/s 240G SSDs with synchronous NAND
MerExt*2 = two OWC Mercury Extreme Pro 6Gb/s 240G SSDs with synchronous NAND
V3Max*2 = two OCZ Vertex 3 Max IOPS 6Gb/s 240G SSDs with synchronous NAND
SwiftAsync*2 = two TransIntl SwiftDATA 6Gb/s 240G SSDs with asynchronous NAND
Electra*2 = two OWC Mercury Electra 6Gb/s 240G SSDs with asynchronous NAND
MEET THE CONTESTANTS
FirmTek's miniSwap (shipping in a few days) features...
- Easy drive swap with no trays or screws or tools required
- Dedicated 6Gb/s rated eSATA port for each drive with direct connect to backplane (no internal cables)
- Supports 7mm, 9.5mm, 12.5mm, and 14.9mm thick notebook HDDs and SSDs
- Aluminum case for durability and efficient passive heat dissipation without fans
- Power and Activity LEDs for each drive
- Smart Power Management: Auto-on or Manual-on
Sonnet Tech's Fusion F2 features...
- Two eSATA ports, one for each drive (which sit side by side)
- Uses the FireWire port as a power source, though an optional AC adapter is available
- Aluminum case with passive fanless cooling
- Comes from the factory wtih two HDDs
Trans International's ProStor525L features...
- Enclosure designed to sit under the MacBook Pro so the drives are configured side by side
- Two easy access bays that require no trays or screws.
- Micro switches on the back let you choose RAID 0, 1, JBOD or SPAN
- Drives share the single eSATA port -- also has FireWire 400, FireWire 800, and USB 2.0 ports
OWC Elite-AL Pro Dual mini features...
- Comes empty for user installation of HDDs or SSDs
- The single eSATA port is shared by the two drives
- The FireWire 800 port for a power source or as an alternative data connection. It also has a USB 2.0 port.
- Micro switches inside the enclosure can be set to RAID 0, RAID 1, JBOD, or SPAN
CRU-DataPort ToughTech Duo features...
- RAID 0 or 1 mode can be set using the LCD display and buttons on the side of the enclosure
- Passive thermal design for optimal heat dissipation - No fans for quiet operation
- Removable drive sleds with built-in locks - No tools or screws needed
- When the eSATA port is active, FireWire port can be used in place of AC adapter for power source.
There are companies other than LaCie And Promise that will introduce Thunderbolt storage in 2012. Also watch for some interesting products like USB3/eSATA6G enclosures and combination Thunderbolt, USB3 and/or eSATA6G enclosures. When they ship, we will test and report.
Feedback or comments? Contact me
, mad scientist.
Also, you can follow me on Twitter @barefeats
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copyright 2011 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
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