The Samsung 950 Pro PCIe SSD Review (256GB and 512GB)
by Billy Tallis on October 22, 2015 10:55 AM ESTAnandTech Storage Bench - The Destroyer
The Destroyer is an extremely long test replicating the access patterns of heavy desktop usage. A detailed breakdown can be found in this review. Like real-world usage and unlike our Iometer tests, the drives do get the occasional break that allows for some background garbage collection and flushing caches, but those idle times are limited to 25ms so that it doesn't take all week to run the test.
We quantify performance on this test by reporting the drive's average data throughput, a few data points about its latency, and the total energy used by the drive over the course of the test.
Both 950 Pros deliver great performance on the destroyer, but the 512GB is outstanding. Clearly the more bursty nature of this test allows the drive to avoid any thermal throttling and deliver the high peak speeds that the PCIe interface is supposed to enable.
The NVMe drives deliver the lowest average service times, but the other PCIe drives are close behind. If there were any moments of thermal throttling like we saw with the performance consistency test, they would greatly inflate the average service time.
The very small number of performance outliers on this test is a good indicator that these drives don't sieze up under the pressure of an interactive workload.
When looking at the more strict latency threshold of 10ms, the 256GB 950 Pro is not significantly better than the good SATA drives, but the 512GB has extremely good control over latency.
Energy usage is not competitive with the high-performance SATA drives. As demanding as it is, The Destroyer still has opportunities for drives to scale back power consumption but the 950 Pro can't do that on our testbed.
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Gigaplex - Thursday, October 22, 2015 - link
It's unlikely Samsung is holding back, as the phenomenon is affecting all brands.ddriver - Monday, October 26, 2015 - link
Corporations do price fixing, why not performance fixing.niva - Wednesday, October 28, 2015 - link
It is possible to do performance fixing, but not likely in this case. Enterprise hardware should generally concentrate on endurance, probably using different binning and better memory. I'm sure they can beef up the drivers too and optimize for certain loads. In general they'll get the most sales by selling in greater numbers. Artificially limiting performance so they can make more profit margin on some (much smaller quantities) hardware being sold to enterprise doesn't make sense.That all being said I guess it is possible.
ShieTar - Monday, October 26, 2015 - link
Yes, there is a DRAM cache. The size of it is listed in the table on the first page of the article.Without this, random writes would still be horrible, as overwriting a complete 128KB block whenever the drive is supposed to write down just 4KB leads quickly to the need of reading, deleting & re-writing the blocks, as no unused 128KB-blocks are left.
Laststop311 - Tuesday, October 27, 2015 - link
its just part of how nand cells works. If you need faster speed 3d xpoint is coming to save the day.Per Hansson - Wednesday, October 28, 2015 - link
The DRAM cache is not used to cache writes.It's large size is mainly for the NAND mapping table.
If writes where cached in DRAM the performance of 4KB random writes would of course be waaay higher than what it is.
And quite extreme dataloss would occur in case of power loss.
virtualbigd - Wednesday, December 16, 2015 - link
Can you elaborate on your reliability point above, for Samsung?virtualbigd - Wednesday, December 16, 2015 - link
I know about 840 EVO, is there something else?Samus - Thursday, October 22, 2015 - link
I have my reservations over Samsung drives, especially since the 840 EVO, but DAMN.jay401 - Saturday, October 24, 2015 - link
Hey if you turn that V upside down, you have the first A-NAND SSD. :D