The Samsung SSD 850 120GB Review: A Little TLC for SATA
by Billy Tallis on November 27, 2017 12:00 PM ESTSequential Read Performance
Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.
The burst sequential read performance of the Samsung SSD 850 120GB places it in the second tier of 120GB-class drives, but it's actually the fastest of the current models. The performance is a clear improvement over the 850 EVO but is about the same as the 750 EVO and the HP S700.
Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data.
On the longer test of sequential reads, the Samsung 850 falls well below the standard set by Samsung's earlier drives and ends up slightly slower than the HP S700. The S700 Pro and ADATA SU800 are in last place with less than half the performance of the 850 120GB.
Most drives show no performance scaling with queue depth on the sequential read test. The older Samsung drives all show some improvement from QD1 to QD2 and are steady after that, while the 850 120GB is simply the same speed across the board.
Sequential Write Performance
Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.
The short burst sequential write speed of the Samsung SSD 850 120GB is comparable to Samsung's other drives in this capacity class, and is better than any other current drive for this segment.
Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.
On the longer sequential write test, the Samsung SSD 850 120GB is tied for second place, though the performance of the 850 PRO far outshines everything else.
As with sequential reads, most of these drives handle sequential writes at the same speed regardless of queue depth. The 850 PRO is the only one to show substantial improvement as queue depths increase. Several other drives experience temporary hits to their write performance as a result of their SLC write caches filling and forcing the drive to perform garbage collection, but most are steady through most of the test.
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boozed - Monday, November 27, 2017 - link
This website really needs a "send corrections" link...mr_tawan - Tuesday, November 28, 2017 - link
corrections is a kind of participation. Using comments is not that bad idea.dgingeri - Monday, November 27, 2017 - link
This sounds like a great OS drive for servers. They don't change all that much, especially if the logs are offloaded to a different drive.sonny73n - Tuesday, November 28, 2017 - link
TLC for servers? No thanks.dgingeri - Wednesday, November 29, 2017 - link
Why not? Write endurance is not a factor when dealing with the boot/OS drive, especially when logs are moved onto another drive. Most servers would see 10-15GB of writes per week on the OS drive, with updates bumping that up more once in a while. This drive would last for decades at that write level.tmanini - Tuesday, November 28, 2017 - link
meh - while there is nothing wrong with one as a boot drive only: once booted you won't benefit much. (this is not a reflection for complex server environs - which then you would never consider this SSD as a contender)lilmoe - Monday, November 27, 2017 - link
The EVOs are priced down on amazon now. Just saying.Magichands8 - Monday, November 27, 2017 - link
They better be. Nothing much to see here.lilmoe - Monday, November 27, 2017 - link
I know... I like Sammy and all, but I'd like to see them go even lower. 2TB SSDs shouldn't be a luxury anymore.mapesdhs - Wednesday, November 29, 2017 - link
Still a very long way from where they used to be. 850 EVO 250GB is currently 85 UKP on Amazon; before the pricing went crazy it was 53 UKP.