Samsung 750 EVO 500GB SSD Review

 

Power requirements and efficiency

Storage device manufacturers by law must provide power
consumption specifications with their storage device products. Quite often
these specifications are quite vague, and rarely, if ever, publish the power
efficiency of their storage devices with regard to how much work a storage
device can do for a given amount of energy consumed. In this article we will
disclose with unprecedented precision, the energy efficiency of some popular
storage devices. 

Myce has now secured a piece of ‘state of the art’ test equipment,
which takes a sample every four micro-seconds, that I will be using to measure
the power consumption of consumer grade SSDs and HDDs. I’m so very proud to be
able to announce that Myce.com, in partnership with Quarch Technology, now aims to bring our
readers the most comprehensive, and accurate, power consumption tests ever
carried out on consumer grade storage devices, to be found anywhere on the
Internet.

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Myce’s Power Testing will be carried out using
Quarch Technology products. More specifically we are privileged that Quarch has
allowed us to use their latest XLC Programmable Power Module (‘XLC PPM’) and we
would also like to take this opportunity to give a huge ‘thank you’ to Quarch
for providing this equipment. The XLC PPM is specifically designed for testing
low power sleep states on modern SSDs and as such has a remarkably accurate low
level current measurement, down to 100
μA (micro amps, or millionths of an
amp). Please click here for details.

Quarch Technology is a world leader in the
supply of testing solutions for the data storage industry and if you would like
any further information please visit their website by clicking here

Let’s take a closer look at the Quarch XLC PPM box in a bit
more detail.

Samsung 750 EVO 500GB SSD Review

Quarch Technology XLC
PPM

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The Quarch Technology XLC PPM is able to provide two power
supply rails to the target SSD. A 12V (volt) rail is required for PCIe based
SSDs, and also for SATA HDDs, SATA HDDs also require the 5V rail to function.
All the power requirements of a SATA SSD are handled by the 5V rail.

As already mentioned, PCIe SSDs also require a 12V rail, but
the second rail is 3.3V rather than the 5V rail used by SATA SSDs. Generally,
most of the PCIe based SSDs that I have tested, which admittedly isn’t a huge
number at the moment, draw their power from the 12V rail, the exception being
the Intel 750 NVMe SSD which uses both the 12V and 3.3V rails.

The Quarch Technology XLC PPM can switch between 5V and 3.3V
on the secondary power output channel as required. So for SATA based SSDs it is
set to 5V, and for PCIe based SSDs, it is set to 3.3V.  

On the left hand side of the Quarch XLC PPM, you can see
trigger in and out sockets. These are used for external triggering of the XLC
PPM. For now, I will not be using this feature.

On the right of the Quarch XLC PPM, you can see the socket
where the main power injection lead connects.

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On the rear of the box (not shown) you will find a USB 2
socket, a power socket (to supply power to the unit) and a Torridon connection
interface, for connecting to external equipment.

My setup.

Although the Quarch Technology XLC PPM can be used on a
single PC, which can act both as host and measurement system, I will be using
two PCs to run the tests. One PC will handle the measurements, and the second
PC will act both as a host for the target SSD, and will also be used to load
the target SSD with data. This will allow me to do some pretty fancy power
consumption tests.

 


I will first show the type of workload being used to load
the SSD during the power consumption test. I will then present the power
consumption graph, and power consumption statistics of the SSD.

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I will display the results in the form of bar graphs, at the
end of each test carried out in this article, so one can compare the results
obtained on all the SSDs featured in this article.

I will use the following IOMeter test patterns to load the
SSD or HDD.

  • 4K random read and write at a queue depth of 1 (to emulate
    a lightweight consumer workload).
  • 4K random read and write at a queue depth of 4 (to emulate
    a medium workload).
  • 4K random read and write at a queue depth of 32 (to
    emulate a heavy workload).
  • 512K sequential read (to emulate reading a sequential file
    from the storage device).
  • 512K sequential write (to emulate writing a sequential
    file to the storage device).

I will also show graphs that will display how much work an
SSD can do for a given amount of energy usage. To do this I will use the
IOMeter results obtained in the tests, and then use a simple calculation to
work out how many IOPS a drive can generate per Watt of power consumed.

The calculation used for the results is IOPS divided by
the amount of power consumed in Watts
.

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Example: The Intel 750 NVMe 1.2TB SSD obtained an IOPS
result of 219,716.47 IOPS for 4K random read at a queue depth of 32, and
consumed 5097mW (5.097 Watts). Divide the IOPS by 5.097 and this shows that the
Intel 750 NVMe SSD can generate 43,107.01 IOPS per Watt of energy consumed for
this particular workload.

For all these tests IOMeter was used to generate the test
patterns and workload for the target SSD. The tests were run for a duration of
approximately 90 seconds.

I will also run a couple of additional tests.

  • Power consumption when the drive is idle.
  • The maximum power required to initialise a drive (this is
    for information only).

All results in this article are derived from the ‘average
power consumption’ and are displayed in milliwatts (mW), unless otherwise
stated.

Power requirements for a lightweight consumer workload. – 4K random read
and write QD1

A typical lightweight consumer workload will generally be at
very low queue depths. Typically at a queue depth of one or less. I’m testing
random data at a block size of 4 Kilobytes, as this block size of small random
files is generally accepted as the most frequently occurring in the consumer
environment.

I will show the chart generated by the Quarch XLC PPM for
the drive that I have tested. I will then show the results in the form of bar
graphs, so one can easily compare with other recently tested SSDs.

There will actually be two bar graphs for each test. The
first graph will show the average power consumption during the test run. The
second graph, which is much more important, will indicate the power efficiency
of the storage device, showing how much work the storage device can do for each
Watt of energy it consumes.

4K Random Read – queue depth 1

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random read QD1

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO consumes the least amount of power, drawing
only 928.85 mW, but let’s see how this translates to power efficiency in the
graph below.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB is the most power efficient SSD in
this test, managing an impressive 12751.91 IOPS per Watt.

4K Random Write – queue depth 1

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random write QD1

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB has an average power consumption
of 1745.84mW, but let’s see how this translates to power efficiency.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO was the third most power efficient in
this test, and managed 20700.29 IOPS per Watt of energy consumed.


Power requirements for a medium weight consumer workload. – 4K random read
and write QD4

A typical medium weight consumer workload will generally be
at a queue depth of four or lower. This workload would typically involve some
multitasking, with perhaps two or three applications running, and processing
data simultaneously.  I’m testing random data at a block size of 4 Kilobytes,
as this block size of small random files is generally accepted as the most
frequently occurring in the consumer environment.

I will show the charts generated by the Quarch XLC PPM, for
the drive that I have tested. I will then show the results in the form of bar
graphs, so one can easily compare with other recently tested SSDs.

There will actually be two bar graphs for each test. The
first graph will show the average power consumption during the test run. The
second graph, which is much more important, will indicate the power efficiency
of the storage device, showing how much work the storage device can do for each
Watt of energy it consumes.

4K Random Read – queue depth 4

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random read QD4

Samsung 750 EVO 500GB SSD Review

In this test the Samsung 750 EVO is consuming an average of
1182.65mW, but again let’s see how this translates to the drive’s power
efficiency in the graph below.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD is extremely power efficient in
this test, finishing in first place.

4K Random Write – queue depth 4

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random write QD4

Samsung 750 EVO 500GB SSD Review

This time the Samsung 750 EVO 500GB has an average power
consumption of 2994.22mW of energy.

Samsung 750 EVO 500GB SSD Review

Here the Samsung 750 EVO 500GB SSD isn’t so power efficient
and finishes this test in fifth place.


Power requirements for a heavyweight consumer workload. – 4K random read
and write QD32

Whilst this workload is unlikely arise for the casual
consumer PC user, it could well appear in a semi-professional consumer
environment, such as in a graphics workstation. This workload would usually
involve heavy multitasking, and having several processes running concurrently
that require constant access to small files located on the storage device for
input or output.

I’m testing random data at a block size of 4 Kilobytes, as
this block size of small random files is generally accepted as the most
frequently occurring in the consumer environment.

I will show the chart generated by the Quarch XLC PPM, for
the drive that I have tested. I will then show the results in the form of bar
graphs, so one can easily compare with other recently tested SSDs.

There will actually be two bar graphs for each test. The
first graph will show the average power consumption during the test run. The
second graph, which is much more important, will indicate the power efficiency
of the storage device, showing how much work the storage device can do for each
Watt of energy it consumes.

4K Random Read – queue depth 32

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random read QD32

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD has an average power
consumption of 1892.5 mW.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB is very power efficient, managing
an outstanding 51681.86 IOPS per Watt of energy consumed.

4K Random Write – queue depth 32

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– 4K random write QD32

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD has an average power
consumption of 2124.4 mW in this test.

Samsung 750 EVO 500GB SSD Review

This translates to the Samsung 750 EVO 500GB being one of the
least power efficient drives in this test.


Power requirements of a storage device when reading and writing sequential
data

Not all of a consumer workload is based around the reading
and writing of small random files. Many files are sequential in nature, and can
vary in size from a few Kilobytes to several Gigabytes, so your storage device
will spend a lot of time reading and writing sequential data.

I’m testing sequential data at a block size of 512
Kilobytes.

There will actually be two bar graphs for each test. The
first graph will show the average power consumption during the test run. The
second graph, which is much more important, will indicate the power efficiency
of the storage device, showing how much work the storage device can do for each
Watt of energy it consumes.

512KB Sequential read

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– Sequential read

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD has an average power
consumption of 2157.02 mW during this test, but let’s see how this translates
into its energy efficiency.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD is the third most efficient
SSD in this test, managing 480.37 IOPS for each Watt of energy it consumes.

512KB Sequential write

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– Sequential write

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD has an average power
consumption of 2242.56 mW during this test.

Samsung 750 EVO 500GB SSD Review

This time the Samsung 750 EVO 500GB SSD is in second place,
managing a very impressive 448.69 IOPS per Watt.


Power requirements of storage devices when they are idle and doing no work
at all

The practical reality relating to power consumption is that
it can be quite erratic and sometimes unpredictable. Some of us will invest in
the most powerful PC we can afford, only to find that the PC can spend quite a
lot of time running and doing absolutely nothing. Storage devices are no
different.

Often we can be sitting idly pondering what to do next, or
perhaps browsing the Internet. When we arrive at a page that interests us, we
will read it, and that can take a fair amount of time to complete. During this
period the storage device will most likely be idle, but still consuming energy.

In this test, I’m measuring how much energy the storage
device consumes when doing no work at all.

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
– Drive idle

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB SSD consumes very little energy
when doing no work at all, drawing only 28 mW of energy.


I will now show a couple of additional tests which are for
information only.

Power requirements to initialise a storage device.

This test is for information and interest only, and in these
results we’re looking at the maximum power consumption figure during
initialisation of each drive, rather than the average power consumption for
each device.

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
SSD – Power up maximum power requirements.

Samsung 750 EVO 500GB SSD Review

The Samsung 750 EVO 500GB requires 2839.94 mW of power to
kick it into life. This test is for information only.


Power requirement trace of an SSD booting Windows 10, in real time.

This test is for interest only, and shows the power
requirements of the review SSD booting Windows 10 to the desktop.

Samsung 750 EVO 500GB SSD Review

Samsung 750 EVO 500GB
SSD – Real time trace of the drive booting Windows 10 to the desktop.

Summary

The power efficiency of the Samsung 750 EVO 500GB SSD is a
mixed bag. It’s very energy efficient when reading data, and writing sequential
data, but when writing random data, its energy efficiency is not the best in
class.

When the Samsung 750 EVO 500GB SSD is doing no work at all,
it is a very energy efficient SSD, consuming only 28mW of energy when idle.

 

 

This concludes our review. To read the final thoughts and
conclusion, click the link below….

 

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