IOMeter test results
I/O Performance
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 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 total MB/s.
Partition alignment and sector boundaries
Windows 7 and Vista 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 OCZ Vertex 4 is 4k boundary aware, and will use these boundaries if possible. Of course it will also remap LBAs for compatibility with the sector boundaries so that 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 write test with repeating data.
The 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. It is said that most 4K random writes take place at a queue depth of only one, and I have been requested to include this test in my reviews.
Queue depth 1
OCZ Vertex 4 SSD – 4K random write (QD1)
At 139.47 MB/s the OCZ Vertex 4 is showing astonishing performance at this queue depth, but this was achieved with the original shipping firmware. Firmware 1.4 is far more sedate with 76.64 MB/s. So why has it dropped from the original shipping firmware?
In this world you get nothing for free. If you’re going to improve performance drastically in one area where it was weak before, then you must pay with a hit in performance elsewhere. However, reducing the QD1 4K random write performance 139MB/s to 76MB/s will go unnoticed in a desktop PC, where it is very unlikely that you would need even 76MB/s at queue depth 1.
Our next 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.
Queue depth 4
OCZ Vertex 4 (Queue depth 4)
At a queue depth of 4, the OCZ Vertex 4 performance is very strong indeed, and is once more well ahead of the other SSDs in this test, however again firmware 1.4 is slightly slower than the original shipping firmware.
Queue depth 32
OCZ Vertex 4 (Queue depth 32)
The SandForce SF-2281 SSD processor is known to scale very well with increasing queue depths, so it’s no surprise to see the two SF-2281 based SSDs doing very well in this test; however they still can’t keep pace with the OCZ Vertex 4, which is once again the fastest SSD.
IOMeter 4K random write test with fully random data.
This test is exactly the same as the test above except that the test data is fully random and is therefore much more difficult to compress. This test was requested as SandForce based SSDs gain a lot of performance by being able to compress data on the fly. While the above test shows the SandForce based SSDs in a best case scenario, the following test will show the SandForce based SSDs in a much more realistic scenario.
Queue depth 4
OCZ Vertex 4 SSD – 4K random write (QD4 with fully random data)
The OCZ Vertex 4 doesn’t compress data on the fly like the SandForce based SSDs, so performance is not affected when it has to deal with data that is not so easy to compress, and it is still miles ahead of the other SSDs in this test.
4K random write queue depth profile
For this test I used various queue depths from 1 – 32 to give you an idea how this SSD performs at different queue depths. For a normal desktop user for lightweight multitasking, the queue depth will rarely rise above 2. For heavy multitasking, the queue depth is unlikely to rise above a value of 8.
The result is below.
If there was ever a test that graphically leaves you in no doubt as to which SSD is the fastest, then this is it. While the two SandForce SF-2281 based SSDs offer huge performance at high queue depths, they are still not as fast as the Everest 2 based OCZ Vertex 4, and what is even more impressive is that the OCZ Vertex 4 reaches this level of performance at much lower queue depths. Even at a queue depth of only 3, it is outgunning the SF-2281 based SSDs at queue depth 32, and for a desktop user this is very important, as typical desktop user patterns are pretty much all at lower queue depths.
Below I present a table of the results in more detail.
IOMeter 4K random 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.
It is said that most 4K random reads take place at a queue depth of only one, and readers have requested that I include this test in my reviews.
Queue depth 1
OCZ Vertex 4 SSD (Queue depth 1)
Firmware 1.4 is again a bit slower than the original shipping firmware, but even then is still ahead of the rest.
Queue depth 4
OCZ Vertex 4 SSD (Queue depth 4)
The Crucial C300 has been King of 4K random read for a long time, but just a few weeks ago the Plextor PX-256M3 ran it very close. There is now a new King of 4K random read, the OCZ Vertex 4 which lifts the performance bar considerably.
Queue depth 32
OCZ Vertex 4 SSD (Queue depth 32)
There are no surprises here, and once again the OCZ Vertex 4 is out in front by a large margin.
4K random read queue depth profile.
This test shows how the review drive scales with increasing queue depths.
Below I present a table of the results in more detail.
The OCZ Vertex 4 is once again exceptional. It’s faster at low queue depths than any of the other SSDs in this test, but it doesn’t stop there, and as queue depths rise it pulls further and further ahead of the other SSDs.
IOMeter 512KB write test with repeating data.
Sequential writing performance is also very important; in this test sequential writing performance is measured.
OCZ Vertex 4 SSD – 512K sequential write
The OCZ Vertex 4 has very good sequential writing performance, but was never going to catch the two SandForce SF-2281 based SSDs when writing data that is easily compressible.
IOMeter 512KB write test with fully random data.
This test is exactly the same as the test above except that the test data is fully random in nature. This test was requested as SandForce based SSDs gain a lot of performance by being able to compress data on the fly. While the above test shows the SandForce based SSDs in a best case scenario, the following test will show the SandForce based SSDs in a more realistic light. In the real world, the data is neither 100% incompressible nor 100% compressible, it is somewhere in between. So please keep this in mind.
OCZ Vertex 4 SSD – 512K sequential write with fully random data
With data that is not so easy to compress, the SandForce SF-2281 based SSDs take a big hit in performance. Not so for the OCZ Vertex 4 with its Indilinx Everest 2 controller, and the Vertex 4 is comfortably the fastest drive.
IOMeter 512KB read test.
This test measures 512k sequential reading performance.
Queue depth 1
As we can see, low queue depth sequential reading performance is significantly better with firmware 1.4.
Queue depth 2
OCZ Vertex 4 512K Sequential write with repeating data
Although the OCZ Vertex 4 has excellent sequential reading performance, it is outgunned by quite a few other SSDs in this test. The margin isn’t huge, but some firmware tweaking to improve “sustained” sequential reading performance would be welcome.
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).
OCZ Vertex 4 SSD – Workstation simulation
The workstation simulation is interesting as the test pattern is more in tune with the real world. Firmware 1.4 is a huge improvement over the original shipping firmware in the OCZ Vertex 4, and in fact puts the Vertex 4 miles ahead of the other SSDs in this test.
Summary
As a desktop SSD, the OCZ Vertex 4 has raised the performance bar by a large margin. At lower queue depths the Vertex 4 is untouchable. It pays no performance penalty with data that is non-compressible, and at higher queue depths it is still a good deal faster with small file random data than any of the other SSDs in this article. Sequential writing performance is excellent especially with non-compressible data, sequential reading speed although excellent, is not quite as fast as some of the other SSDs in this article.
All in all, the OCZ Vertex 4 is one very fast SSD.by Dee senior adminstrator and reviewer
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