X-bit labs

2.5-Inch External Hard Drives with 120GB Storage Capacity (page 3)

Category: Storage

by Aleksey Meyev

[ 04/02/2007 | 01:58 PM ]

Performance in Intel IOMeter

Sequential Read & Write

IOMeter is sending a stream of read and write requests with a request queue depth of 4. The size of the requested data block is changed each minute, so that we could see the dependence of the drive’s sequential read/write speed on the size of the data block.

The HD-227FW with a FireWire interface delivers unrivalled performance irrespective of the data chunk size. Its max speed is 37.74MB/s on 128MB and larger blocks. Although the USB 2.0 interface has a higher theoretical bandwidth than IEEE1394a (60MB/s against 50MB/s), it has no advantage in practical applications. Compare the two brothers with different interfaces: the FireWire model is faster than its USB counterpart by one third on average. The WD Passport is the fastest of the models with a USB interface, providing a speed of almost 30MB/s when reading 64KB and larger data blocks.

It’s no different with sequential writing: the HD-227FW is still an overall leader while the WD Passport is ahead among the USB-interfaced devices. The WD drive acts up somewhat, however. It is even ahead of the FireWire drive on 64KB data blocks but just refuses to process 1024KB blocks, suffering a fivefold performance hit!

It is these sequential IOMeter patterns that are most important for mobile storage media because such media are mostly used exactly for sequential reading or writing whereas operation modes simulated by patterns like Database, File-Server or Web-Server are less likely to happen to an external HDD. We use the latter patterns to explore the theoretical capabilities of an external HDD.