Onnto TB-S120 hard disk enclosure

Note: Pricing for this product is in US$.

The capacity of external USB hard drives is going up all the time. Unfortunately, most only offer a USB 2.0 connection, which limits how quickly you can get your data onto or off the drive.

The Onnto TB-S120 hard disk enclosure is a flexible solution to the problem. It's an empty case with three different connection standards, namely USB 2.0, FireWire 400 and FireWire 800. And in our tests, we found using the latter rewards you with transfer speeds twice that of USB.

The Onnto TB-S120 is neatly constructed from an aluminium extrusion with silver-painted plastic ends. Inside a metal tray supports the circuit board, with the three interface types and a DC power input on one end.

With FireWire, you can daisy-chain several devices together, and to this end the Onnto TB-S120 includes two FW 800 ports for this purpose (but only one port for FW 400).

Also included in the box is a power adaptor, and sadly we found this was required for USB operation. Only with FireWire connections was the Onnto TB-S120 drive happy to be entirely bus-powered.

We found it straightforward to install a WD Scorpio Blue hard disk, a 2.5in drive firmly secured in place by four screws to the PCB.

Using Simpli HD Tach 3.0 for speed tests, we found that USB 2.0 and FireWire 400 were very close in read performance - 27.4MB/s and 26.0MB/s respectively. In data write tests, the FW 400's 21.5MB/s figure nudged out USB's 19.1MB/s.

And it was with FW 800 that the unit came into its own, able to read at 60.2MB/s and write at 27.2MB/s, with bursts of up to 82.9MB/s.

Impressively, FireWire only consumed 1-2 percent system CPU, while USB needed 17 percent.