HDTach 3.0.4.0
HD Tach will test 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 your system for proper performance, and compare your performance with others. HD Tach is very easy to use, quick, and presents data in easy to read graphs, including the ability to compare two storage devices on screen at the same time for easy analysis.
Bursts are provided only for your review. SSD's don't cache the same way HDD's do (in many cases they don't cache reads at all), so burst testing typically results in figures that are lower than the sequential throughput figures.
SandForce controllers have always been a bit tricky in playing nicely with HDTach. The way it accesses the device under test makes some HDDesque assumptions that are *very* sensitive to SandForce firmware tuning. Perhaps *too* sensitive, as the differences seen above don't translate into real world differences in performance.
HDTach feeds the tested drive a continuous string of small sequential read requests. This is a single threaded operation, which means the SSD doesn't get to see what's coming next. The lower the QD=1 latency of the controller pipeline, the better the numbers we see from this test. It doesn't equate to real-world maximum throughput, but it does mean something for analysis, which is why we include these results.
More realistic sequential figures are present on the next page (HDTune).
Very thorough review Allyn.
Very thorough review Allyn. The move to try out the new flash size using sandforce instead of Indilinx perplexed me at first, but then I thought that they would probably want to experiment the hardware change with a tried and true firmware.
looks great nice work Allyn!
looks great nice work Allyn! Though you should really include more 500+ gb units in your reviews for completeness 😀
Thanks! We usually try to
Thanks! We usually try to cover ranges, but the 3.20 is not available in a >240GB capacity.
I am still using my OCZ
I am still using my OCZ Vertex 3 SSD with no problems. Vertex 3.20 does not deserve that Vertex name. Come on, OCZ, you need to do better SSD Vertex SSD products.
Hey Allyn,
What components
Hey Allyn,
What components make up the overhead that prevents SSD’s from reaching the max 6gbps bus speed? Is it all scsi frame overhead or are there other limiting factors?
Thanks.