UPDATE: I’ve written up a more through review of using eSATA on my MacBook Pro here.
This is the first of several tips I want to write up with regards to squeezing every last bit of performance out of Parallels Desktop for the Mac.
One of the tried and true tips for running virtual machines has always been: “Use an separate drive to house your VM”
While this is true for Windows computers running VirtualPC or VMWare, this isn’t the case w/ Intel based Macs running Parallels Desktop for Mac. The reason is that the current crop of MacBooks ( regular and pro ) have SATA hard drives inside, not your standard EIDE ( or PATA ). The current MacBook SATA bus thus runs at a maximum of ~1.5 Gb/s ( ~150MB/s ). Compared to maximum USB 2.0 speeds of ~480 Mbit/s (~60 MB/s), your internal hard drive will be much faster.
Now, there is some credibility to putting a faster drive ( RPM wise ) in an external USB enclosure is better than your internal hard drive. However, even if the drive is 7,200 RPM ( compared to 5,400 RPM drives in the MacBook ), you’re still cutting your pipe almost by two-thirds. So while your hard drive will be able to find data a little quicker, your data will still be slow to come back to you.
However, there is one case where an external drive DOES make more sense: External SATA (eSATA ). eSATA is a external version of SATA that is now starting to show up in devices. eSATAs throughput of ~3.0Gb/s makes regular SATA like pokey. MacBook pro users can pick up several enclosures that support both USB 2.0 and eSATA. A couple of solid manufactures are Icy Dock and Vantec. However, the only option for adding eSATA ports to your MacBook Pros is to add a eSATA ExpressCard/34 expansion card. (Sorry MacBook users, no ExpressCard for you.)
There are only a couple of vendors that make a eSATA card that is supported by OS X. The Tempo card is pretty expensive at $110, but SIIG makes a eSATA card that retails for $80.
Certainly, once you add up a eSATA enclosure, express card and perhaps a new SATA drive, this little project could get a little pricey.
But for 3.0Gb/s speeds, isn’t it worth it?