Samsung 950 Pro M.2 NVMe 512GB SSD Review

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.

IOMeter is probably the most versatile of all the synthetic
benchmarks. Its ability to be configured to generate a multitude of different
I/O traffic is unmatched. Another great feature of IOMeter, is the capability
to test any storage metric that you can think of, providing you know how to
configure the assignments. The reviewer also has complete control over things
like queue depth, block size, whether the traffic is random, sequential, or
even a mixture of both.

Partition alignment and sector boundaries

Windows 10, Windows 8.1, Windows 7, and Windows 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 and 8 will use 4k boundaries
if they can. The Samsung 950 Pro M.2 NVMe SSD 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.

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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, Windows 8, 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.

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Queue depth 1

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 4K random write (QD 1)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

At 246.2 MB/s the Samsung 950 Pro M.2 NVMe SSD’s performance
is outstanding, and it finishes this test in second place.

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.

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Queue depth 4

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung
950 Pro M.2 NVMe 512GB SSD (QD 4)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

At a queue depth of 4, the Samsung 950 Pro M.2 NVMe SSD is
excellent, and finishes this test in third spot.

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Queue depth 32

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung
950 Pro M.2 NVMe 512GB SSD (QD 32)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Once the Samsung 950 Pro M.2 NVMe 512GB SSD reaches a queue
depth of four, there isn’t much more performance to be attained with higher
queue depths when writing small random files. However, at 431.29 MB/s, the
Samsung 950 Pro is still performing extremely well, and once again takes third
spot in this test.

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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 with fully random data

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe SSD – 4K random write (QD 4 with fully random data)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

The Samsung 950 Pro M.2 NVMe SSD pays no penalty when
writing data which is incompressible, and finishes this test in second place.


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, with 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 results are shown below.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

As we can see, the Samsung 950 Pro M.2 NVMe SSD has
outstanding performance at low queue depths but, after reaching a queue depth
of 2, performance doesn’t increase with higher queue depths. One should note
that, with this level of performance at low queue depths, the fact that the Samsung
950 Pro M.2 doesn’t really scale well after a queue depth 2 isn’t really a
problem.

Below I present a table of the results in more detail.

Samsung 950 Pro M.2 NVMe 512GB SSD Review


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

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2 512GB
SSD – 4K random read (QD 1)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

In this test the Samsung 950 Pro M.2 NVMe SSD has
outstanding performance, and finishes in first place.

Queue depth 4

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 4K random read (QD 4)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

At a queue depth of four, the Samsung 950 Pro M.2 NVMe is
outstanding, and is the fastest SSD in this test.

Queue depth 32                             

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 4K random read (QD 32)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

At a queue depth of 32, the Samsung 950 Pro M.2 NVMe SSD is
once again showing outstanding performance, and finishes this test in second
place.

4K random read queue depth profile.

This test shows how the review drive scales with increasing
queue depths.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Below I present a table of the results in greater detail.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Queue depth 32 with four threads

This test is new, and designed to simulate an extremely
heavy reading workload, and is unlikely to occur even in a heavyweight consumer
computing session. The test is simply to measure the maximum throughput a PCIe
NVMe SSD can achieve.

The workload consists of reading 4K random data at a queue
depth of 32, and running this workload with four threads.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 4K random read QD32 with 4 threads

The result is interesting to say the least. Whilst it’s
unlikely that a consumer workload would require this sort of performance, it is
still interesting to see that the Samsung 950 Pro can reach 1.278.46 GB/s, and
reach an incredible 312124.8 IOPS, which is more than the 300K IOPS that
Samsung claims is achievable.

Let’s compare the results with other recently tested PCIe
NVMe SSDs.

Samsung 950 Pro M.2 NVMe 512GB SSD Review


IOMeter 512KB sequential write test with repeating data.

Sequential writing performance is also very important; in
this test sequential writing performance is measured.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 512K Sequential write with repeating data

Samsung 950 Pro M.2 NVMe 512GB SSD Review

The Samsung 950 Pro M.2 NVMe SSD gave an excellent turn of
speed in this test, and finished in second place.

512K sequential write – Queue depth profile

While most sequential writes will rarely rise above a queue
depth of two, it has been noted from SATA analyzer traces that with more
demanding tasks, queue depths can rise very close to a queue depth of four.
This is why I now include queue depth profiles for sequential read and write.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

512K sequential write
– Queue depth profile

Below I present a table of the results in more detail.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

IOMeter 512KB sequential write test with fully random data.

This test is almost 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.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 512K sequential write with fully random data

Samsung 950 Pro M.2 NVMe 512GB SSD Review

With data that is not so easy to compress, the SandForce SF-2282
based OCZ REVODrive 350 took a big performance hit, whilst the Samsung 950 Pro
M.2 NVMe SSD retains its writing performance, and finishes this test in top
spot.


IOMeter 512KB sequential read test QD1.

This test measures 512k sequential reading performance at
very low queue depths.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 512K sequential reading test (QD 1)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

The Samsung 950 Pro M.2 NVMe SSDs have outstanding
sequential reading performance at very low queue depths, finishing in first and
second place in this test, and miles ahead of the other SSDs. Interestingly,
the 256GB version proving to be slightly faster than the 512GB SSD.

IOMeter 512KB sequential read test (dual threaded).

This test measures 512k sequential reading performance QD2.

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – 512K sequential reading test (QD 2)

Samsung 950 Pro M.2 NVMe 512GB SSD Review

At a more realistic queue depth the Samsung 950 Pro M.2 NVMe
SSD is still showing outstanding sequential reading performance, and finishes this
test in first place.

512K sequential read – Queue depth profile

While most sequential reads will rarely rise above a queue
depth of two, it has been noted from SATA analyzer traces that with more
demanding tasks, queue depths can rise very close to a queue depth of four.
This is why I now include queue depth profiles for sequential read and write.

Please note that in the following graph, I do not have the
lowest possible score set at zero. This is purely to allow the graphs to be
easier to read, but starting with a lowest possible score other than zero, gives
the impression that there are large differences between competing SSDs with
regard to performance, so please keep this in mind. 

Samsung 950 Pro M.2 NVMe 512GB SSD Review

512K sequential read
– Queue depth profile

Below I present a table of the results in greater detail.

Samsung 950 Pro M.2 NVMe 512GB SSD Review


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).

Samsung 950 Pro M.2 NVMe 512GB SSD Review

Samsung 950 Pro M.2
NVMe 512GB SSD – Workstation simulation

Samsung 950 Pro M.2 NVMe 512GB SSD Review

The ‘workstation’ simulation sorts the men out from the
boys, with its mixed reads and writes. This test shows how an SSD could behave with
a heavy workload, in a graphics, or video workstation environment. The Samsung
950 Pro M.2 NVMe SSD has excellent mixed read/write performance, and finishes
the test in second place.


Summary

All in all, the Samsung 950 Pro M.2 NVMe SSDs has performed extremely
well in our IOMeter tests. The Samsung 950 Pro M.2 NVMe SSD has outstanding
reading performance, and writing performance is of a very high standard. It
also comes as no surprise that the larger capacity Samsung 950 Pro is a good deal
faster than the 256GB version.

 

Now let’s head to the next page where we will look at how
the Samsung 950 Pro M.2 NVMe SSD performs using a new benchmarking
application….

 

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