As previously implied, all the performance tests were conducted using the eSATA connection. This provides far greater throughput (MB per second), and lower latency (seconds per request) than does USB, with the downside that the host can access only the first defined array.
With two disks in the array and configured as RAID 0, our basic overview benchmark ATTO shows us:
That’s ... not bad. That's not bad at all! It’s not quite as fast as if the disks are connected to the motherboard SATA connectors, but it’s certainly no slouch at around 90% of the onboard SATA controllers.
ATTO concentrates on the first few MB of the disk, which sits on the outside of the platters, so in a lot of ways the performance data from ATTO is generally “as fast as it gets”. HDTach gives us performance data across the entire volume, as well as isolating the effects of any cache RAM:
Holy cow that’s good. Interestingly you’ll probably notice that performance actually increases over the first 60% of the array to a maximum of nearly 180MBps, then falls away to just under 120MBps. That’s no slouch.
HDTune gives us more data still – showing the difference between sequential and random access:
Ah, consistency. That’s a good sign. We even replicate the sequential performance curve from HDTach, so it looks like the two results are valid.
The random performance is quite interesting. The result of ~50 IOPS is about what we’d expect to see from a single disk (actually, it’s a fraction lower), so we’re really not seeing any advantage from the 2 disk RAID 0 array for random performance.
