MacBook Pro External Storage:
CalDigit VR mini versus others
Originally posted July 6th, 2009, by rob-ART morgan, mad scientist
Updated July 17th, 2009, with new Sonnet Fusion F2 results
If you have a MacBook Pro with an ExpressCard/34 slot, you have the option of external eSATA enclosures, which offer much more speed than FireWire 800 or USB 2.0 ports. One very interesting option is the CalDigit VR mini.
Though the VR mini supports RAID 0, 1, and JBOD, being speed freaks, we chose RAID 0 when gathering some large sustained transfer rates using QuickBench 4.
GRAPH LEGEND
MP293 = CalDigit VR mini connected to Mac Pro 2.93GHz using spare internal SATA port
MBP280 = CalDigit VR mini connected to MacBook Pro 2.8GHz 'late 2008' using Sonnet SATA Pro*
MBP260 = CalDigit VR mini connected to MacBook Pro 2.6GHz 'early 2008' using Sonnet SATA Pro*
Fusion F2 = Sonnet Fusion F2 dual drive RAID 0 enclosure connected to MacBook Pro 3.06GHz 'mid 2009' using Sonnet SATA Pro*
M500*2 = Dual Seagate Momentus 7200.4s (500G) in separate TransIntl miniXpress825 S enclosures connected to the MacBook Pro 2.8GHz 'late 2008' using Sonnet SATA Pro*
FW800 = CalDigit VR mini connected to MacBook Pro 2.6GHz 'early 2008' using FireWire 800 port
Single = Single internal OEM Hitachi Travelstar 7K320 notebook drive inside the MacBook Pro 2.6GHz 'early 2008'
(* Sonnet Tempo SATA Pro ExpressCard/34)
INSIGHTS
The CalDidit VR mini mated with the Sonnet Tempo SATA Pro ExpressCard/34* creates a compelling external storage option for any MacBook Pro with an ExpressCard slot. The speed is good for dual notebook RAID 0 enclosure running off one eSATA port using a quad interface bridge. Though the Fusion F2 is faster, keep in mind that it requires two eSATA ports and two eSATA cables. And it is SW RAID vs HW RAID.
(* The Sonnet Tempo SATA Pro ExpressCard/34 is unique among SATA ExpressCards in that it is the only true SATA adapter. Other brands say "SATA" but are actually using USB protocols. The result is that the Sonnet Tempo Pro produces much higher transfer rates. For example, when we connected the OCZ Vertex SSD to various SATA ExpressCards, the Sonnet Tempo Pro was 55% faster reading and 103% faster writing compared to the fastest alternative SATA ExpressCard.)
We included the results for VR mini running off the FireWire 800 port to show why we prefer using a Serial ATA configuration. No matter how many devices you hang off of a FireWire 800 port, it won't go much faster than a single drive. The main advantage of FireWire has been that it provides bus power. Most eSATA storage devices require an AC adapter. CalDigit's VR mini (and Sonnet Fusion F2) cleverly uses the FW800 port as a power source when running data through the eSATA port, though a conventional AC adapter is available.
The VR mini comes with RAID Tool software that makes it easy to configure it in RAID 0, 1, or JBOD mode. An LCD panel on the front of the enclosure gives you mode and status info. In the case of the Fusion F2 we used Disk Utility's RAID function to stripe the two drives.
The CalDigit VR mini we tested had dual Hitachi Travelstar 7K320 notebook drives. They offer a version with dual 500G drives. In the future, faster notebook drives with larger capacity will appear, though the maximum possible transfer speed for such a setup is around 200MB/s -- the limitation of the ExpressCard interface. We illustrated this with the Sonnet Fusion F2 enclosure and with the dual miniXpress825 S enclosure setup we tested (see graphs) where each drive had its own dedicated eSATA channel.
If you need a storage solution that goes faster than 200MB/s, you'll need something like dual SSDs inside your MacBook Pro. The only other way to get faster storage is with a Mac Pro using three or more drives in a RAID 0 set (each drive with its own data channel).
