HD Tune Pro
Version and / or Patch Used: 4.00
Developer Homepage: http://www.efdsoftware.com
Product Homepage: http://www.hdtune.com
HD Tune is a Hard Disk utility which has the following functions:
Benchmark: measures the performance
Info: shows detailed information
Health: checks the health status by using SMART
Error Scan: scans the surface for errors
HD Tune Pro gives us accurate read, write and access time results and for the last couple of years has gained popularity amongst reviewers. It is now considered a must have application for storage device testing.
Reading across the drives with a queue depth of one, Vector 128GB keeps pace with the 256GB version. OCZ built in a feature that artificially limits single queue depth read performance. For a while, we thought it was a burden, but we couldn't explain why Vertex 4 felt faster than what the benchmarks stated. We have a little more understanding about it now.
If you limit a single request to 350MB/s, you have headroom for another task to take place without interrupting the first. It's a bit like having two thin driveways to your garage instead of one wide one. You and your spouse are trying to leave at the same time and both of you are in a hurry. If you have one wide driveway you both can drive fast because you're not worried about dropping a tire off the edge. The driveway isn't wide enough for you to drive side-by-side so you have to go one in front of the other. If your spouse is in the front and drives slower, you're delayed because of the latency of your spouse driving slower. The way OCZ worked it is with two thinner driveways. You can't drive as fast on the thinner driveway, but you don't get delayed by other traffic.
When we first saw this behavior on Vertex 4 with the initial firmware the limit was just 200MB/s. OCZ increased the limit in later firmware releases to just over 300MB/s and Vector increases it to around 350MB/s. We'll talk about this a little later on in the review because the artificial limit affects some benchmarks and makes their reported performance seem lower than what you'll find in real-world situations. At the same time, when copying data the 350MB/s limit is the maximum you'll get when moving data by copy and paste.
OCZ has another trick up its sleeve, this time we see it when writing a lot of data to the drive. HD Tune Pro uses 64KB data, but when we move the test to 128KB, the 'storage mode' affect goes away.
This one is a little harder to explain. We've read that storage mode doesn't kick in until after half of the flash has data on it, but we've taken that theory off the table. If that were true then our Data on Disk testing would show a massive performance decrease when we move from 25% full to 50% full, but it doesn't.
Here we see the actual benchmark run. The performance drops at 50%, but it has more to do with the block size of the data and how fast we put the data on the drive. At the 64KB size the drop in performance when blasting the drive with data is at 50%, but with 128KB data the drive doesn't drop at all.