There is little point of having an SSD drive that has
blazing sustained reading and writing speeds, if the drive can’t handle reading
and writing of small random files. If you intend to use your new SSD drive to
store and run your operating system, then the drive must be able to cope with
the many small random files that Windows will write to the drive continually.
So I feel it is very important to test how many of these random files that a
drive can handle in one second. I believe that anything over 1,000 I/O’s per
second would be enough for most users running a consumer grade mainstream PC,
and should provide a smooth and fast running system. But obviously, the more I/O’s
that a drive can handle, the faster the drive will feel and leave more headroom
for those huge multitasking sessions that users sometimes engage in.
The things that I will look at are the total I/O per second and
Partition alignment and sector boundaries
Windows 7 will automatically align a partition to 4k boundaries
during partition creation, Windows XP won’t. It is imperative that an SSD’s
partition is aligned. Windows XP is also restricted to sector boundaries, while
Windows 7 will use 4k boundaries if it can. The Plextor PX-256M2S is 4k
boundary aware, and will use these boundaries when it can. Of course it will
also remap LBAs for compatibility with the sector boundaries so the drive can
be used with Windows XP.
IOMeter allows us to set the sector boundaries for
conducting the tests, and I have therefore set the sector boundaries at 4K,
which means the IOMeter tests are valid for Windows 7 and Windows Vista users.
XP users will not be able to obtain such results.
I will provide a screenshot of the tests on the review drive
for those of you who like to see the actual test result. All the comparison
drive results are represented in the form of graphs.
If any of you would like to see a screenshot from any
IOMeter test on a particular drive, please feel free to request one, and I’ll
post the screenshot in the forum thread.
All the IOMeter tests create a 10GB data set on the target
drive, and each test is run for a duration of 3 minutes.
IOMeter 4K random (outstanding I/Os = 4, 32) write test.
Our first test involves creating continual 4KB random files
on the target drive with IOMeter. I use a 4KB file size, as it is believed that
Windows will create and modify many of this size of file constantly in the
background during a typical Windows session. I will use queue depths of 4 and
32 for these tests on the OCZ Vertex 3, OCZ Vertex 2, and Crucial RealSSD C300.
(Queue depth 4)
(Queue depth 32)
The Plextor PX-256M2S is left well behind many of the other
SSDs in this test; even increasing the queue depth to 32 didn’t really lift
performance. The question is will the lack of 4K random writing performance
have a negative impact on the performance of the drive in the real world?
We will find out the answer to that question a little later
in this article.
IOMeter 4K random (outstanding I/Os = 4, 32) Read test.
If there are many 4k files created, then that must also mean
that many 4k files need to be read. This test measures 4k reading performance.
(Queue depth 4)
(Queue depth 32)
The Crucial RealSSD C300 was always mighty with 4K random reading
performance, and is well over 3 times faster than the PX-256M2S, which is also
well behind the SandForce based SSDs. This time however, the 4K reading
performance does get better with the PX-256M2S as the queue depth increases.
IOMeter 512KB (outstanding I/Os = 2) write test.
Sequential writing performance is also very important; in
this test sequential writing performance is measured. I use a queue depth of 2
to make sure the drive has a constant load.
The Plextor PX-256M2S has performed extremely well in this
test, and is the second fastest drive.
IOMeter 512KB (outstanding I/Os = 2) read test.
This test measures 512k sequential reading performance. I
use a queue depth of 2 to make sure the drive has a constant load.
Sequential reading performance is very impressive, and the Plextor
Px-256M2S is only very slightly behind the OCZ Vertex 3.
IOMeter Workstation simulation (outstanding I/Os = 64).
When running applications you will find that there is a
mixture of small random files, and larger sequential files being created and
read. Not only that, it isn’t just one file at a time. In this test I measure a
simulated workstation pattern, with a queue depth of 64 (threaded).
The Plextor PX-256M2S has performed quite well, but once
again its lack of small random file performance lets it down in this test.
Once again it’s a mixed bag for the Plextor PX-256M2S. It is
now very apparent that the PX-256M2S has very strong sequential performance,
but small random file performance is having a negative impact on some IOMeter
Now let’s head to the next page for some real world tests….