SSD Performance HD Tach

HD Tach

HD Tach is a physical performance hard drive test that uses a special kernel mode VXD to get maximum accuracy by bypassing the file system.

The HD Tach sequential read test is a little bit different from other benchmarks. Most benchmarks create a file on the hard drive and test within that file. The problem is that modern hard drives use a zone bit recording technique that allows different read speeds depending on where the data is located. Data on the outside of the drive is much faster than data recorded on the inside.

SSD itself - no caching enabled (that's seriously fast)

HDtach run 1 - very obvious HDD expected behaviour

HDtach run 2 - You can see cached data kick in

HDtach run 3 - very interesting performance

When we look at write performance we see 109 MB/sec in this test at the first cached run, that's classic HDD performance. Once we reach the 2nd run we are already at 292 MB/sec. The 3rd run shows 291 MB/sec read performance with burst speeds up-to 324 MB/sec.

Write performance could not be tested again as we can not cache an unformatted and partitioned RAW volume.