The Samsung 950 Pro PCIe SSD Review (256GB and 512GB)
by Billy Tallis on October 22, 2015 10:55 AM ESTIdle Power Consumption
The idle power consumption I'm reporting here and in the Bench database is what's achievable on our 2015 testbed with PCIe ASPM disabled for the sake of system stability. Samsung's initial announcement of the 950 Pro specified an idle power consumption of 1.7W, which these drives manage to stay under. Samsung's later specs mention 70mW idle and 2.5mW DevSlp power draw. The former figure is something we hope to be able to verify in the future, but our power meter isn't sensitive enough for measuring DevSlp power.
As stated earlier, the power numbers for the PCIe drives are more of a worst-case scenario, due to our testbed being unable to enable their power saving modes. These active idle power levels have nevetheless been growing with each new PCIe drive from Samsung.
Trim Validation
Strictly speaking, NVMe doesn't have the TRIM command. The NVMe Deallocate command is the equivalent to the ATA Trim command, and since the trimcheck tool relies on the OS and filesystem to issue the command, it works without modification on NVMe drives.
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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