Comparing eSATA To USB For External Drives

I’ve just purchased a new SATA-based external hard drive to use with demos and I thought I would share some details about the performance gain over my older ATA-based hard disk.

I’ve been doing a few demonstrations of Microsoft SoftGrid using VMware Workstation on my laptop with an external USB attached hard drive and I’ve also got a couple of user group presentations coming up. So I wanted to squeeze some better disk performance out of this setup because every second counts during demos.

Before I read Mark’s post about USB attached hard drive performance in his notebook, I was hoping to add a second internal hard drive to my Dell laptop, but unfortunately Dell doesn’t provide a media bay type disk enclosure for this model. I was looking into using Firewire until I considered eSATA. I found this review of the Belkin SATA ExpressCard very useful when looking at what I might expect from eSATA.

Here’s what I ended up ordering:

To power this drive I have to connect the included USB power lead. I’m not sure if I used a better quality eSATA cable that it would provide enough power, but carrying the extra cable is not too much of a hassle. I’ve performed these tests on my laptop which has the following hardware:

  • Dell Vostro 1400
  • Intel Core 2 Duo (2.2GHz, 4MB Cache)
  • 4GB RAM
  • Windows Vista x64

To test the performance of my disk setup, I’ve used HD Tune because they offer a free version and it’s easy to use. I tested the performance of my original hard disk (Seagate Momentus 5400.3 80GB ATA/100 5400RPM 16MB 2.5”) connected to this laptop via USB. The result stays consistent right up until the end of the test:

Orignal disk performance over USB

When I performed the same test on a desktop machine the throughput was about 5MBps higher and was consistent to 100%. This is the performance of the new hard disk over a USB connection:

New disk performance over USB

And the performance of the same hard disk over an eSATA connection using the Belkin ExpressCard:

New disk performance over eSATA

Overall I’m pretty happy with the performance of the new disk. It more than doubles the performance of my older disk yet still in a portable package and my VMs feel much much snappier.

 Original (USB)New SATA (USB)New SATA (eSATA)
Minimum transfer rate21.4MBps27.8MBps33.7MBps
Maximum transfer rate25.2MBps29.5MBps65.4MBps
Average transfer rate24.8MBps29.2MBps52.3MBps
Access time16.5ms15.1ms14.6ms
Burst rate19.6MBps22.9MBps75.1MBps
CPU utilisation13.6%17.1%3.4%