 |
Review: Samsung 860 EVO SATA 250GB Reviewed by: J.Reynolds Provided by: Samsung Firmware: RVT01B6Q |
Introduction
Welcome to Myce’s review of the Samsung 860 EVO 250GB SATA
SSD (hereafter referred to as the Samsung 860 EVO).
The Samsung 860 EVO is the successor to Samsung’s very
successful 850 EVO.
The Samsung 860 EVO uses Samsung’s latest 64 layer, V-NAND
3bit MLC technology, and a newly designed MJX controller. It is available in three
form factors – 2.5 inch, M.2 2280, and mSATA.
Samsung promises better sequential and random performance as
well as improved endurance. Please read on to see how the 860 EVO performs.
Like many of the latest Client SSDs the Samsung 860 EVO uses
an ‘SLC Write Cache’. Samsung now refers to its SLC Write Cache technology as
‘Intelligent TurboWrite’ and this is how they outline its capability -
Intelligent TurboWrite
Samsung first provided TurboWrite technology with the 840
EVO. With TurboWrite, write speeds are significantly accelerated during data
transfers by creating a high performance SLC write buffer in the SSD. If a
consecutive write operation (i.e. no idle time) exceeds the size of the buffer,
the transfer will exit TurboWrite and proceed at an “after TurboWrite” speed.
Until now, for most SATA devices, a small amount of SLC write buffer used to be
enough for most use cases, but given the much higher expected workloads with
recent data trends, this buffer would be insufficient. To address this issue,
Samsung introduced intelligent TurboWrite with the 960 EVO in 2016. Now the 860
EVO also has adopted this powerful feature. Intelligent TurboWrite identifies
user workloads intelligently and defines the appropriate SLC buffer. With the
250GB model, for example, if the user data is under 3GB, intelligent TurboWrite
uses the preallocated (default) TurboWrite region, similar to that of the
previous 850 EVO. However if the user wants to write more than 3GB, the 860 EVO
can use an additional 9GB Intelligent TurboWrite region for a total SLC buffer
of 12GB. The Intelligent TurboWrite region takes advantage of idle capacity,
so if the SSD does not have more than 27GB of free space for the 250GB model,
intelligent TurboWrite will not operate. Please also note that this algorithm
does not affect SSD endurance, because the total amount of data users write on
the SSD is unchanged.
We will look out for signs of the TurboWrite technology and
its impact on performance in our testing. Please note that the 250GB drive as
tested in this review has a significantly smaller Total Write cache size than
the larger capacity models in the range.
Packaging
Let’s start by having a look at the Samsung 860 EVO’s
packaging –
The Samsung 860 EVO includes an Installation Guide and
instructions for downloading Samsung’s excellent ‘Samsung Magician’ software.
Market Positioning and Specification
This is how Samsung positions the 860 EVO –
Here is Samsung’s specification for the 860 EVO –
Now let's head to the next page, to look at my approach
to testing Client SSDs.....
Testing Approach
When reviewing the performance of a Storage solution there
are three basic metrics to look at:
1.
IOPS – the number of Input/Output Operations per Second
2.
Bandwidth – the number of bytes transferred per second (usually measured
in Megabytes per second, ‘MB/s’)
3.
Latency – the amount of time each IO request will take to complete
(usually, in the context of Solid State Storage solutions, measured in
Microseconds, which are millionths of a second).
It is true to say that IOPS and Bandwidth had both been growing
rapidly before the advent of Solid State Storage, but Latency can only be
significantly decreased by eliminating mechanical devices, and thus Latency is
the single most important improvement that Solid State solutions deliver to
enhance performance.
Latency in a technical environment is synonymous with delay.
In the context of a Solid State solution it is the amount of time between an IO
request being made, and when the request is serviced.
Bandwidth, also commonly referred to as ‘Throughput’, is the
amount of data that can be transferred from a storage device to a host, in a
given amount of time. In the context of Solid State solutions it is typically
measured in Megabytes per second (MB/s).
A great Solid State solution offers an effective balance of
all three metrics. High IOPS and Bandwidth is simply not enough if Latency
(the delay in an IO operation) is too high.
Queue Depth is the average amount of IO requests
outstanding. If you are running an application and the Average Queue Depth is
one or higher and CPU utilisation is low, then the application’s performance is
most probably suffering from a ‘Storage Bottleneck’.
It is true to say that a typical PC user will very rarely
cause a modern SSD to see a Queue Depth greater than 1 or 2. So for Client SSDs
we need to primarily focus on performance at low Queue Depths.
Another important aspect to consider with an SSD is the
state of its NAND when an IO task begins. When an SSD is new, or immediately
following a purge (a Secure Erase for an SATA device) being performed, it is in
a Fresh out of Box (‘FOB’) state and in this state all of its Blocks of NAND
are clean and able to immediately accommodate the writing of new data.
Typically SSDs are supplied with a greater capacity of ‘Total NAND’ than their stated
‘User Capacity’ and the difference between them (Total NAND – User Capacity) is
known as an Over Provision (‘OP’) at the firmware level.
If an IO Task that involves writing new data can complete
without the supply of clean blocks being exhausted it will complete more
quickly than if blocks must first be cleaned on the fly before writes can be
accommodated. The number of free blocks available may also impact on performance
(think of it this way - the more free blocks there are the easier it is to find
one to write to). An SSD will continue to write to clean blocks until there
are no more available after which it must then free up blocks by completing an
Erase/Write cycle on the fly before it can write new data. Blocks that have
been written to are flagged as being able to be cleaned when either the logical
address they are associated with in an Operating System is written to again or
when a Trim instruction is sent by the OS to indicate that a range of logical
addresses (which map to physical blocks) no longer contain live data (for
example, in Windows, Trim instructions are sent to an SSD, when a file is
logically deleted, to indicate that all of the physical blocks which contained
the file no longer hold live data).
An SSD’s controller performs a process known as ‘Garbage
Collection’ which gathers together spaces that no longer hold live data so that
it can create clean blocks in preparation for accommodating the writing of new
live data. Blocks are contained within Pages and only complete Pages can be
erased in preparation to accommodate new writes, so one of the responsibilities
for Garbage Collection is to shuffle blocks out of partially filled pages so
that whole pages can then be cleaned. Garbage Collection can be performed as a
regular background task and on the fly. The effectiveness of an SSD’s Garbage
Collection has a significant impact on its long term performance. It is
important to note that a Trim command does not itself clean blocks and it will
always take a bit of time for Garbage Collection to follow up and actually
complete the cleaning process.
An SSD maintains a table, that can be used by an OS, which
holds the mapping of its physical blocks to logical addresses. Effectively,
the OP is increased above that set at the firmware level whilst the drive’s
user capacity is not full of live data. In Windows a user can effectively
choose to underline their commitment to increasing the level of OP by not fully
allocating the drive’s user capacity to partitions.
When a drive is compelled to clean blocks on the fly to
accommodate new data it moves from an FOB state towards what is known as a ‘Steady
State’. A Steady State is achieved when performance is steady and no longer
changes significantly over time. Testing of Enterprise SSDs is always
performed when a drive is in a Steady State. It is fair to say that typically
a Client SSD will spend most of its time in an FOB state (or near to FOB state)
and it's in this state that our testing is performed using the Desktop PC.
Remember though that one can expect to see a performance drop when the drive
holds increasing amounts of live data, as the pool of free blocks (the
effective OP) becomes smaller.
Whilst most Client SSD users need not be overly concerned
about Steady State performance we do push an SSD to its limits as part of our
testing on the OakGate Test Platform.
So what performance characteristics make for an excellent
Client SSD?
Put simply, we look for a solution that provides both
excellent Sequential IO performance and excellent Random IO performance.
Excellent Sequential performance supports the rapid transfer of large amounts
of data from one place to another, such as when copying a movie, loading a game,
or running a backup. Excellent Random IO means that a drive will support the
rapid reading, writing, and updating of relatively small files that are
randomly placed on a drive (such as is required by the Windows Operating System),
the launching of applications, or by a database based application. Sequential
performance is most often measured in terms of MB/s (Megabytes per Second) and
Random IO is most often measured in terms of IOPS (IO Operations per Second).
Modern SSDs deliver low Latency and support tens of thousands of Random IOPS
and whilst very few PC users really need support for such a high level of IOPS
it does mean that every IO will be fast.
Manufacturers most frequently quote the headline maximum
Sequential Read and Write Bandwidth for a drive. They also regularly cite the
maximum IOPS level for 4K Random Reads and Writes. Operating Systems are known
to make extensive use of the 4K IO size and this is why strong 4K Random Read
and Write performance is considered important.
I use two test platforms for testing Client Storage
solutions –
Firstly, a Desktop PC, with the following specification: CPU
– Intel Core I7 6700K, Motherboard – Asus Maximus VIII Extreme (Z170), System
Drive – Intel 750 400GB, GPU – EVGA GeForce GTX970 FTW, RAM – 32GB Corsair
Dominator Platinum, Cooler – Corsair H110i GTX, Windows 10 using Intel RST
15.7.1.1015 and with C States disabled in the BIOS, as this ensures reasonable
consistency from storage benchmarks.
Secondly, an OakGate Storage Test Platform, which is
introduced in an article that you can view by clicking here.
The OakGate Test Platform can be thought as a professional, laboratory
instrument where the test environment is managed strictly and consistently so that
test results from multiple solutions can be compared with great confidence and
precision.
The Desktop PC is used to run a cross section of the most
respected and commonly used storage performance benchmark software, including
AS SSD, Anvil, Crystal Disk Mark, ATTO, and PCMark 8 Storage, together with a
number of real world file copies. Most of these benchmark programs are freely
and easily available for you to run on your own PC. There is a good case for reviewers
to test an SSD as a System Drive, as arguably this is the way in which most
people will use an SSD. However, I choose to test drives as a spare as I
believe this makes it far easier to provide a consistent basis for product
comparisons, which I feel is most important.
The OakGate Test Platform is used to provide an accurate
baseline for a drive’s performance in all of the key aspects of performance,
including Sequential Reads and Writes, Random Reads and Writes, and Random
Mixed Reads and Writes. The OakGate Test Platform is also used to investigate
how a drive behaves when it is pushed to its limits and to measure a drive’s
power consumption characteristics. (All testing on the OakGate Test Platform
is conducted with fully random data and is aligned to 4K boundaries)
In the presentation of test results I include comparisons
with other products I have tested in the same way on the same platforms.
Now let's head to the next page, to look at the results
for the Desktop PC Synthetic Benchmarks.....
Desktop PC – Synthetic Benchmarks
AS SSD
As its name suggests AS SSD was developed specifically to
measure the performance of SSDs. It measures Sequential Read and Write
performance with an IO Size of 16MB and a Queue Depth of 1. It measures Random
4K Read and Write for a Queue Depth of 1 and for 64 Threads. 64 Threads
generates a Queue Depth of 64 (please note that SATA drives support a maximum
Queue Depth of 32, so they are at a disadvantage in this test to NVMe devices,
which support queue depths of 128 or more). The Access Time AS SSD reports is
for 512Byte sequential reads and writes.
The 4K random Reads and Writes performance is particularly
relevant to a drive’s ability to act as a Windows system drive. I use the
default test file size of 1GB.
AS SSD produces a score for Read Performance, Write
Performance and an Overall Score.
The scores are calculated as –
Overall score = (Seq Write x 0.15) + (Seq Read
x 0.1) + (4K Read * 2) + 4K Write + 4K-64Thrd Write + (4K-64Thrd Read * 1.5)
Read score = (Seq Read * 0.1) + 4K Read + 4K-64Thrd
Read
Write score = (Seq Write *0.1) + 4K Write + 4K-64Thrd
Write
For Client SSDs, I feel that there should be an
even greater loading given to the Queue Depth 1 4K Read and 4K Write results
but nevertheless AS SSD is a quick and useful benchmark. I always use a 1GB
test file. We would expect a modern SATA SSD to achieve an overall score
of 1000+.
The latest version of AS SSD can be downloaded here.
Here is the AS SSD result for the Samsung 860 EVO -
This is a very striking result. I am particularly impressed
by the 4K Read result of 53.22 MB/s, which is the fastest I have seen for an SATA
SSD.
Here is a comparison of the overall AS SSD score with the
other products I have tested -
Anvil’s Storage Utilities
Anvil’s Storage Utilities tests Sequential Reads and Writes
with an IO Size of 4MB, Random 4K Reads and Writes at Queue Depths of 1, 4 and
16 and Random 32K and 128K Writes.
The scores are calculated as –
Overall Score = Read Score + Write Score
Read Score = (Seq 4MB = MB/s x 1) + (4K = MB/s
x 4.5) + (4K QD4 = MB/s x 2.75) + (4K QD16 = MB/s x 1.75) + (32K = MB/s x 1) +
(128K = MB/s x 1.5)
Write Score = (Seq 4MB = MB/s x 1) + (4K =
MB/s x 4) + (4K QD4 = MB/s x 3) + (4K QD16 = MB/s x 3)
I always use a Test size of 1GB and 100%
Incompressible data.
The latest version of Anvil’s Storage
Utilities can be downloaded here.
Here is the Anvil result for the Samsung 860
EVO -
Here is a comparison of the Anvil Total score with the other
products I have tested -
Crystal Disk Mark
Crystal Disk Mark is a widely respected benchmark, which is
often used by manufacturers as a basis for publishing their ‘headline’
sequential read and write speeds. I always run the test with One Thread and a
Queue Depth of 32 (which generates a Queue Depth of 32, being the maximum Queue
Depth supported by SATA drives), a 1GB test file, Random data and 5 passes. The
benchmark performs sequential IO with an IO Size of 512K for the Seq Q32T1
test, sequential IO with an IO Size of 1MB for the Queue Depth 1 Seq test and
Random IO with an IO Size of 4K for the 4K (Queue Depth 1) and the 4K Q32T1
test.
Crystal Disk Mark can be downloaded here (I use the
standard edition).
Here is the CDM result for the Samsung 860 EVO -
You can see that the Sequential Read and Write speeds as
specified by Samsung, of 560MB/s and 520MB/s respectively, have both been
exceeded.
ATTO
The ATTO benchmark tests Sequential IO for a large range of
IO Sizes. I always run the test with the default Queue Depth of 4.
ATTO can be downloaded here.
Here is the ATTO result for the Samsung 860 EVO -
Again, you can see that the maximum Sequential Read and
Write speeds, as specified by Samsung, have both been exceeded.
Now let's head to the next page, to look at the results
for the Desktop PC Real World Benchmarks.....
Desktop PC – Real World Benchmarks
PCMark 8 Storage Benchmark 2.0
This is how Futuremark describes the PCmark 8 Storage
Benchmark –
PCMark 8 Storage benchmark is ideal for testing the
performance of SSDs, HDDs and hybrid drives.
Using traces recorded from Adobe Creative Suite,
Microsoft Office and a selection of popular games, PCMark 8 Storage highlights
real-world performance differences between storage devices. You do not need to
have these applications installed on your system to run the Storage benchmark.
The PCMark 8 Storage benchmark test contains the
following workload traces: Adobe Photoshop light, Adobe Photoshop heavy, Adobe
Illustrator, Adobe InDesign, Adobe After Effects, Microsoft Word, Microsoft
Excel, Microsoft PowerPoint, World of Warcraft and Battlefield 3
You can read a detailed description of each storage test and
how the overall score is calculated in the PCMark 8 Technical Guide by clicking
here.
The results from this benchmark are, I feel, a valuable
insight into how a drive will support real world applications.
I thank Futuremark for providing Myce with a license to use
PCMark 8 Pro.
Here is the result for the Samsung 860 EVO -
Exceeding an overall score of 5,000 is very impressive.
Here is a comparison of the overall score with the other
client products I have tested -
File Copy Benchmarks
FastCopy is a useful program for recording how long copying
files to and from a drive takes. FastCopy can be downloaded here.
A Ram Disk (a virtual drive held in RAM) is used as the
source drive when a file is ‘copied to’ the test drive and is then used as the
destination when a file is ‘copied from’ the test drive. This ensures that the
test drive is on the critical path for the time taken.
Here are the results -
Copy a Blu-ray Movie to the Samsung 860 EVO
It is interesting to note that the Samsung 860 EVO is
significantly slower than the WD Blue 3D in this test. This is because the
file size exceeds the 860 EVO 250GB’s maximum SLC Write Cache size of 12GB and
therefore the transfer speed drops to the post TurboWrite speed for part of the
transfer. The WD Blue 3D’s SLC Write Cache technology allows the cache to be
reused once it has been flushed down to normal NAND and thus the WD Blue 3D
only experiences a short and temporary drop in speed whilst the flushing takes
place.
Copy a Blu-ray Movie from the Samsung 860 EVO
Copy a Game to the Samsung 860 EVO
Again the Samsung 860 EVO is slower than the WD Blue 3D in
this test as the file size exceeds the 860 EVO 250GB’s maximum SLC Write Cache
size of 12GB.
Copy a Game from the Samsung 860 EVO
Copy a folder of JPEGs to the Samsung 860 EVO
Copy a folder of JPEGs from the Samsung 860 EVO
Now let's head to the next page, to look at the results
for the OakGate FOB Tests.....
OakGate Platform - ‘Fresh out of Box’ Tests
These tests provide a highly consistent basis for comparing
solutions. The sequence of tests begins with a purge of the drive to ensure
that it starts in a FOB state.
The tests cover all of the essential IO performance
characteristics.
Sequential Writes
This test performs 20 seconds of Sequential Write IOs for
each combination of Queue Depths 1, 4 and 32, and IO Sizes of 4K, 128K, and
1024K. IO traffic is limited to an IO Range of 1GB (which is equivalent to a
test file size of 1GB).
Here are the results for the Samsung 860 EVO –
[masterslider id="62"]
Here is a comparison of the 1024K, Queue Depth 32,
Sequential Write performance with the other products I have tested to date –
This is an excellent result which exceeds Samsung’s
specification of 520 MB/s.
Let’s also have a look at how the Sequential Writes Power
Consumption compares, but to do this fairly we must divide the average MB/s by
the average Milliwatts to get a value for the effective work done. Here is the
result –
You can see that the Samsung 860 EVO has an outstanding
level of power efficiency.
Sequential Reads
The test performs 20 seconds of Sequential Read IOs for each
combination of Queue Depths 1, 4, and 32, and IO Sizes of 4K, 128K, and 1024K.
IO traffic is limited to an IO Range of 1GB.
Here are the results for the Samsung 860 EVO –
[masterslider id="63"]
Here is a comparison of the 1024K, Queue Depth 32,
Sequential Read performance with the other products I have tested to date –
This is an excellent result for an SATA drive. The Samsung
860 EVO is pushing to the very limit of the SATA Bus bandwidth and it exceeds Samsung’s
specification of 560 MB/s.
Random Writes
The test performs 20 seconds of Random Write IOs for each
combination of Queue Depths 1, 4, and 32, and IO Sizes of 4K, 16K, and 32K. IO
traffic is limited to an IO Range of 1GB.
Here are the results for the Samsung 860 EVO –
[masterslider id="64"]
Here is a comparison of the 4K, Queue Depth 1, Random Write
performance with the other products I have tested to date –
This is an excellent result for an SATA drive.
The 4K Random Write IOPS for an IO Size of 4 and Queue Depth
of 32 was 70,000 which is a long way short of WD’s specified value of 90,000
IOPS.
Let’s have a look at the Latency Distribution for the 4K, QD
1 performance –
This graph shows the Latency for every IO that was performed
in the 20 seconds of traffic. It shows the Number of IOs (IO Count) that fell
within a particular period of Time (Microseconds). The red line plots the Time
against the percentage of total IOs performed.
You can see that the Samsung 860 EVO achieves a high level
of consistency and that 99.9% of all IOs have a Latency of 40 Microseconds or
less.
Remember this test was run in an IO Range of 1GB and the Samsung
860 EVO uses an SLC Write Cache. Assuming the 860 EVO 250GB uses its default
Write Cache size of 3GB for 4K Random IO then an IO Range of 1GB would maximise
the opportunity for Cache hits to occur (i.e. for a block that is written to
already be in the SLC Write Cache). So, I decided to rerun this test with an
IO Range of 64GB to see if performance would slow down, this is the result –
Random Writes to an IO range of 64GB
The drop in speed is apparent for a Queue Depth of 32, where
for example, 4K performance has dropped from 413.67 MB/s to 302.4 MB/s.
Random Reads
The test performs 20 seconds of Random Read IOs for each
combination of Queue Depths 1, 4, and 32, and IO Sizes of 4K, 16K, and 32K. IO
traffic is limited to an IO Range of 1GB.
Here are the results for the Samsung 860 EVO –
[masterslider id="66"]
Here is a comparison of the 4K, Queue Depth 1, Random Read
performance with the other products I have tested to date –
This is an excellent result for an SATA drive.
The 4K Random Read IOPS for an IO Size of 4, and Queue Depth
of 32, was 84,003, which is a long way short of Samsung’s specified value of 98,000
IOPS.
4K Random Mixed Reads/Writes
The test performs 20 seconds of 4K Random Mixed Reads/Writes
for each combination of Queue Depths 1, 4, and 32, and Read/Write ratios of
0/100, 30/70, 50/50, 70/30, and 100/0. IO traffic is limited to an IO Range of
1GB.
Here are the results for the Samsung 860 EVO –
[masterslider id="67"]
Here is a comparison of the 4K Mixed Random 50% Read/50%
Write, Queue Depth 1 performance, with the other products I have tested to date
–
This is an outstanding result.
Now let's head to the next page, to look at the results
for the Oakgate Platform - Steady State Tests.....
OakGate Platform - Steady State Tests
Sequential Writes to Steady State
This test starts with a purge (Secure Erase), so that the
drive is in a FOB state, and then performs 128K Sequential Writes until twice the
drive’s User Capacity has been written to.
Here is a graph showing the resulting Write Bandwidth over
time -
You can see that the performance level falls to a post
TurboWrite speed of just over 300 MB/s after around 25 seconds. Curiously, the
write speed then steps up at around 300 seconds, and around 760 seconds, to
finally settle into a steady state of roughly 330 MB/s.
Let’s zoom in and have a closer look at the first minute -
You can see that the Write Cache (Intelligent TurboWrite)
has enabled the write speed to remain at over 520 MB/s until the total Write
Cache of 12GB (default of 3GB plus intelligent allocation of 9GB, for the 250GB
drive) has been exhausted.
4K Random Writes, FOB to Degraded (Steady State) to Recovered
This test is designed to fully degrade the drive’s
performance and then see how it recovers following a Trim and a period of Rest.
In this test I start with a purge
of the drive to take it to a FOB state.
- FOB Performance – 4K Random
Writes Bandwidth
I then test the FOB 4K Random
Write Performance at Queue Depths of 1 and 32, in an IO Range of 16GB, the
result was as follows –
- Sequential Writes to two times User Capacity
I then performed 128K Sequential Writes to the drive for
twice the drive’s user capacity (as in the previous Sequential Writes to Steady
State test).
- 4K Random Writes for 1 Hour
This was immediately followed by performing 4K Random Writes
to the drive for 1 hour. Here is a graph showing the resulting Bandwidth over
Time –
You can see that the Random 4K Write performance drops
significantly after around 50 seconds (when the SLC Write Cache is exhausted)
and the performance then settles and heads towards a Steady State of around 27
MB/s.
- Fully Degraded, 4K Random Write ‘Steady State’
Performance
I then immediately test the 4K Random Write Performance, in
an IO Range of 1GB (as we did in the initial FOB test), and the result was as
follows -
You can see that performance has dropped significantly
compared to the test performed in the FOB step. At this stage it is fair to
say that the drive’s performance is fully degraded and in a Steady State. It’s
as bad as it can get!
- Trim and Rest for 5m
I then liberally sent Sequential Trim commands to the drive
for a minute (to ensure that the drive’s entire range of logical blocks (= User
Capacity) was trimmed).
I then let the drive rest for 5 minutes before retesting 4K
Random Write performance again. The result was –
- ‘Recovered’ 4K Random Write Performance after Trim and
5 minutes rest
The outcome was –
You can see that the level of performance has improved but
it has not yet approached full recovery.
I the reran the entire series of test steps but with a rest
time of 10 minutes –
- ‘Recovered’ 4K Random Write Performance after Trim and
10 minutes rest
The drive has recovered a bit more but is still not
approaching full recovery even with a rest time of 10 minutes. This is
disappointing when compared to the WD Blue 3D drive that we tested recently,
which had nigh on fully recovered after 5 minutes. To be fair, I should say
that it is unlikely that any Client SSD will ever be degraded to this extent.
Now let's head to the next page, to look at the
Conclusions from this review.....
Conclusions
There is no doubt that the Samsung 860 EVO is an outstanding
drive as it has set new high water marks for an SATA drive in most of our
performance tests. The only minor reservation I have, is the relatively small
size of the Write Cache in the 250GB model, as this can slow down the copying
of large files to the drive somewhat (as was seen in our Real World Copy Tests
on page 4), however I doubt if this will ever be a concern with the larger
capacity models, which have a much bigger write cache (personally I prefer the
write caching approach which sees the SLC Cache being made available again, after
its contents have been flushed down to NAND, as was seen with the WD Blue 3D
that we reviewed recently). Indeed, the 1TB and upwards models also suffer
little or no loss in post TurboWrite sequential write performance.
I was particularly impressed with the Samsung 860 EVO’s low
Queue Depth 4K Random Reads and Writes – no doubt it will prove to be an excellent
system drive.
Samsung has indicated that the recommended UK price for the
860 EVO 250GB will be GBP £90.49, which makes it great value.
So the price point is highly competitive but, for example,
the excellent WD Blue 3D 250GB is priced at GBP £83.99, so it is not without
competition. Things are definitely ‘hotting up’ in the value segment of the
SATA Client SSD market.
It is worth noting that the Samsung 860 EVO range has strong
endurance and, for example, the 250GB model has an endurance of 150 TBW (Total
Terabytes Written), which is 50% more than the WD Blue 3D 250GB.
I am pleased to award the Samsung 860 EVO 250GB our rating
of "Outstanding" and name it as an "Editor’s Choice".
