Multithreaded Read & Write Patterns

The multi-threaded tests simulate a situation when there are one to four clients accessing the hard disk at the same time. The depth of the outgoing request queue is varied from 1 to 8.

We’ll discuss diagrams for a request queue of 1 as the most illustrative ones. When the queue is longer, the speeds depend but little on the number of applications.

The eSATA-connected Teac is unrivalled when reading one thread. It is followed by the Transcend. Next go the other 250GB models with USB interface whereas the 300GB models with USB interface are the slowest again. Interestingly, the eSATA-connected 300GB Teac is considerably faster than its 250GB counterpart.

The eSATA interface loses its advantage at two read threads. The 300GB model is still in the lead, but the gap is small. The 250GB model sinks suddenly to last place.

When the number of threads is increased further, the eSATA-connected drives from Teac restore their leading positions. The 250GB model doesn’t show a performance hit whereas the 300GB model slows down less than the USB-connected models do. You can see the Transcend being the worst drive at three threads but faster than the USB-connected 300GB models at four threads.

The eSATA-connected drives from Teac are in the lead when writing one thread. They enjoy a 10MBps lead over the closest pursuer. The Transcend is the slowest drive here but it is not far worse than the other USB-connected models. You can see the USB-connected 300GB drives are as fast as the 250GB models in this test.

When the number of write threads is increased to two, the USB-connected models remain unaffected whereas the eSATA-connected drives from Teac lose some speed, but still stay on top places.

The standings do not change much when there are even more write threads to be processed. You can only note the Transcend speeding up suddenly at four threads and rising from last place to the middle of the group of the USB-connected drives.