Sequential Performance – HDTach, HDTune, File Copy, YAPT (sequential)

We have shifted over to combining our results into two groupings for consumer reviews. First up is sequential performance:


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. HDTach tests sequential performance by issuing reads in a manner that was optimized more for HDD access, but this unique method has proven useful in evaluating the sequential response time of SSDs. The accesses are relatively small in size (2k), and are issued with a single working thread (QD=1). The end result is that devices with relatively IO high latency will not reach their ultimate rated speed.

With QD=1 and small sequential reads taking place, the SSD 750 gets unseated by Samsung's NVMe SM951.


HDTune tests a similar level of features as compared with HDTach, but with a different access pattern. Thus provides us with an additional set of benchmark numbers to compare between storage configurations. CPU utilization has proven negligible with modern processing horsepower, and is no longer included. Additionally, we do not include write performance due to HDTune's write access pattern not playing nicely with most SSDs we have tested it on.

We have HDTune configured to perform large block reads, but the test is performed after the HDTach run. It is likely that the Phison controller just doesn't like reading back data that was previously written in small blocks (HDTach's write pattern). To clear this up, I configured Iometer to fill one of the Phison SSDs completely and then perform 128k sequential reads on that completely full SSD:

As you can see, no issue hitting 560+ MB/sec reads from a Phison S10 controlled SSD. That means the S10 simply does not like how HDTach writes to them during the previous tests we performed.

PCPer File Copy Test

Our custom PCPer-FC test does some fairly simple file creation and copy routines in order to test the storage system for speed.  The script creates a set of files of varying sizes, times the creation process, then copies the same files to another partition on the same hard drive and times the copy process.  There are four file sizes that we used to try and find any strong or weak points in the hardware: 10 files @ 1000 MB each, 100 files @ 100 MB each, 500 files @ 10 MB each and 1000 files at 1 MB each.

Most results are a fairly tight pack, but there are a few outliers. The Vector 180 had a significant issue we covered during that review, but the same does not explain why the HyperX Savage turned in such slower numbers while creating the 500x 10MB files. The test was repeated three times and turned in numbers within a second on each attempt. The best we can guess is that the firmware tuning of the Savage simply doesn't mesh well with that particular file size being written.

While the HyperX Savage had a quirk during the file creation test, it turned in the fastest figures on the file copy test, even beating the Samsung 850 Pro. All three Phison controlled SSDs did very well here, taking point in nearly every test.


YAPT (yet another performance test) is a benchmark recommended by a pair of drive manufacturers and was incredibly difficult to locate as it hasn't been updated or used in quite some time.  That doesn't make it irrelevant by any means though, as the benchmark is quite useful.  It creates a test file of about 100 MB in size and runs both random and sequential read and write tests with it while changing the data I/O size in the process.  The misaligned nature of this test exposes the read-modify-write performance of SSDs and Advanced Format HDDs.

It's apparent that all SATA SSDs tested are saturating (or nearly saturating) their 6Gb/s link. That dip in the Vector 180 results is explained here.

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