7. Ez-Bus-Mini Being Tested As An External Hard Disk

First, we want to take a look at the performance of the Ez-Bus-Mini being used as an external hard disk on the USB 2.0 interface of the notebook. For comparison purposes, we added a 2.5" Travelstar 40GNX, Model IC25N020 ATCS05-0 2.5" hard disk. At 5400 rpm, it not only rotates faster, but is also has a considerably larger cache with eight megaBytes.

The theoretical bandwidth of the USB interface is 480 Mbps, which is just short of 60 MB/s. In practice, however, transfer rates of only up to a maximum of 32 MB/s are achieved, even with external desktop hard disks with USB 2.0 interfaces.

The two following illustrations show the transfer rates established by Winbench 99 Ver2.0.

Data transfer chart of the 1.8" Ez-Bus-Mini...

...and the 2.5" Travelstar 40GNX

As you can see, the transfer rates of both disks are similar. For Apricorn's Ez-Mini-USB, the transfer rate lies somewhat above 20 MB/s and drops to approximately 12 MB/s towards the middle of the disk. The faster rotating 2.5" disk from Hitachi reached rates between 26 MB/s and 14 MB/s on the USB 2.0 interface. The mean access times were 21.2 ms and 17.5 ms respectively. In both cases, the CPU load was just under 15 percent.

Apricorn's Ez-Mini-USB doesn't have to shy away at all from comparisons to larger and nominally faster hard disks.