HD Tach Tests
HD Tach tests the sequential read, random access and interface burst speeds of your attached storage device (hard drive, flash drive, removable drive, etc). All drive technologies such as SCSI, IDE/ATA, 1394, USB, SATA and RAID are supported. Test results from HD Tach can be used to confirm manufacturer specs, analyze systems for proper performance and compare your performance with others.
This benchmark is intended to determine the maximum read or write speed on the device at various locations. Hard drives, for example, have faster read/write speeds at the inside edge (mapped to block 0) of the device, so it is useful to see the difference in speed. The maximum sustained speed (lowest speed on the device) is an important metric for real time sequential access applications. The maximum speed may be important to a power user that would like to partition the drive into a high speed partition and low speed partition.
Shown in red above, is the HDD when connected to the motherboard's IDE channel. Alternatively in blue, we have the performance when installed in the Gigapod III. As we can see form the graph, performance with the HDD connected to the IDE channel is much better, starting off with a throughput of 60MB/s and tapering off to around 35MB/s towards the end. In coma prison, performance with the HDD installed in the Gigapod, is steady at around 30MB/s. Obviously the drive's performance doesn't change and it is the interface (USB) which is limiting the devices throughput in the latter case.