Brennan’s Blog

I am reading Scott Hanselman's blog about Virtual Machines and External Hard Drive throughput. It shows some metrics which try to make the point that the optimal USB 2 throughput is higher than the output from the external drive. However, it is assuming the optimal throughput is sustained over time. In a lunch conversation Chris (optionScalper) explained that he prefers FireWire over USB due to the sustained performance of the FireWire architecture. He has had recent hard drive problems so he has looked into this more closely than I have.

But I did a quick Google search and found a page which shows the contrast of FireWire vs USB 2. What you will see is the "sustained" speed of FireWire is maintained while USB 2 will degrade over time.

As a lay person I can only assume that USB, which was originally designed for peripherals such as a keyboard, mouse and perhaps a low resolution webcam, was very different than FireWire which was designed to transfer large amounts of media from video recording devices which demands sustained data throughput. For the purpose of running a virtual machine from an external drive you would want sustained throughput. If you are just holding a pile of files on the drive which you access occasionally you are good with USB 2. But actual performance tests should be done to check this assumption. (I will do a live test once I have my PC prepped for it.)

Personally, I purchased a killer drive (7200RPM, 16MB cache) and a dual USB/FireWire drive enclosure so that I can get the best of both worlds. My work laptop does not have FireWire so I use the USB 2 connection. At home I use a $15 FireWire card I purchased at a nearby computer store. On CDW.com you could get a USB 2/FireWire Combo PCI card for $40.

Once I finally get my hands on a working 1GB memory chip for my PC I should be ready to actually run the virtual machines which was the reason for purchasing this external hardware. Unfortunately the memory chip I have sitting in a static free bag on my desk is faulty.