Performance Comparisons – TRIM Speed
Thanks to the plethora of data we have at our disposal from the new suite, I can derive some additional interesting data that nobody seems to have been paying any attention to yet. Have you ever deleted a large file and then noticed your system seem to hang for some time afterward? Maybe file moves from your SSD seemed to take longer than expected?
That's your problem right there. In the above capture, a 16GB file was deleted while a minimal level of background IO was taking place. Note how that IO completely stalls for a few seconds shortly after the file was deleted? That's a bad thing. We don't want that, but to fix it, someone needs to measure it and point it out. Enter another aspect of our new testing:
Latency Percentile data was obtained while running a 'light' (1000 IOPS) workload in the background while files of varying sizes were deleted. The amount of latency added during the deletions was measured, compared with a baseline, and correlated with the sizes of the deleted files. The result is how much latency is added to the active workload per GB of file size that was deleted. In short, this is how long you may notice a stutter last after deleting a 1GB file.
To avoid confusion, I've maintained the performance-based sort from the mixed test for these charts. Here you can tell that some drives that did perform well on that test stick out a bit here when it comes to how they handle TRIM. Ideally, these results should all be as close to 0.000 as possible. Higher figures translate to longer performance dips after files have been moved or deleted.
This is another result sourced from a different segment of data. While our suite runs, it issues a full drive TRIM several times. Some of those times it is done on an empty SSD, while other times the SSD was full. Any difference in time taken is measured and calculated, normalizing to a response time per GB TRIMmed. In short, this is how long an otherwise idle SSD would hang upon receiving a TRIM command for a 1GB file. These times are shorter than the last chart because the SSD controller does not have to juggle this TRIM with background activity and can throw all of its resources at the request.
All Samsung parts did great here, with the MX500 behaving quite poorly (Crucial is looking into this issue as it was reported to them in tandem with our review of that product).
Everything looked fine for the 860's so far, but there was a significant issue that the 860's demonstrated but was not caught by any of the charting methods above. It stemmed from the assumption that a 'clean' (previously TRIMmed) SSD would perform a subsequent TRIM nearly instantly. This had always been the case – until now:
The above chart contains the clean (empty) and dirty (full) TRIM times, corrected for capacity. These were the values used to calculate the deltas in the previous chart. Focusing on even or odd items, note how the clean TRIM takes significantly longer to execute than the interleaved 850 Series products. The 860's take significantly longer here – so long in fact that the 0.012 s/GB value from the 860 PRO 4TB derives from that SSD taking nearly a minute (49 seconds) to partition and quick format under Windows. This same operation also occurs during a Windows install, and that operation sitting stalled for nearly a full minute gets into the territory where a typical user may suspect the system has hung (there is no feedback during a TRIM operation, only an unresponsive system). Smaller capacities will see a proportionally shorter delay for the same operation, but it remains significant when compared against the preceding 850 Series products.
I wonder how much cost is
I wonder how much cost is saves by moving to more dense nand and a smaller pcb footprint? Seeing the performance, it looks to me this was more of a shrink than a improvement.
Agreed. It’s as if they were
Agreed. It's as if they were trying too hard to make the SSD as economical as possible to produce, causing it to fall short in some areas.
It is a SATA SSD, they can’t
It is a SATA SSD, they can’t improve the performance much until the SATA bottleneck is lifted on the host side. Perhaps SATA IV is in order but I believe that will never happen. The 850 series already maxed out the SATA bus, so not exactly sure what performance improvements you would like to magically see Samsung improve upon. They already implemented improvements via M.2 PCIe ssd’s. If you want faster than SATA, you have to move on from SATA. Simple as that.
I agree: it’s as if the
I agree: it’s as if the storage “oligopoly” has conspired
to maintain an artificially low ceiling on 2.5″ SSD speeds.
Several years ago, we proposed a “SATA-IV” standard that
upped the transmission clock to 8G (like PCIe 3.0 lanes)
and changed the 8b/10b legacy frame to the 128b/130b
“jumbo frame” that is already standard in PCIe 3.0:
8 GHz / 8.125 bits per byte = 984.6 MB/second
i.e. exact same throughput as a single PCIe 3.0 lane.
Admittedly, that is not a massive increase; nevertheless,
one could easily approximate one NVMe port with
four such SSDs in a RAID-0 array, and the wiring
topologies for such a RAID array are ubiquitous.
FYI: here’s a copy of our SATA-IV Proposal to the
Storage Developer Conference in 2012:
And, now that the PCIe 4.0
And, now that the PCIe 4.0 standard has been released,
a future SATA-IV standard should support a 16 GHz clock:
16G / 8.125 bits per byte = 1,969.2 MB/second.
Thus, 4 such SSDs in a RAID-0 array should max out
at ~ 7.87 GB/second (no overhead). Yes, the SATA
protocol does have more inherent overhead, but
its installed base is already HUGE. Increasing the
clock rate and upgrading to jumbo frames should be
a piece o’ cake for storage industry manufacturers.
And, RAID controllers could still support PCIe 3.0
edge connectors, while increasing the clock speed
on their SATA connectors to 16 GHz. Maybe Allyn
could offer this suggestion to Areca?
I doubt there will be another
I doubt there will be another SATA spec for SSD drives. SSD drives will move too PCIe and SATA will be for slower bulk storage.
Allyn, I think the last trim
Allyn, I think the last trim chart may have the wrong x-label, not sure, I got confused there.
You are correct! Thanks for
You are correct! Thanks for the catch. It is now fixed.
Hopefully the price of the
Hopefully the price of the 850’s will go down rather than be discontinued.
Allyn, pop quiz of the day.
Allyn, pop quiz of the day.
I have 3 256gb 850 pros in RAID 1 on my boot drive (I have no sensitive data on the raid). I have all my programs/games on this “drive”. I am approaching 200gb of free space left. As you know with todays games that could be 4 new AAA titles. I have toyed with the idea of getting a single 500gb drive windows and all apps, leaving my 7xx gb raid for Steam only. Is there any benefit to doing that with one of these drives or should I just snatch up another 256gb 850 pro and increase my raid?
***I am on Z97 so an NVME boot drive isn’t possible.
RAID 1 with three drives?
RAID 1 with three drives?
Yea… I mean raid 0. Got
Yea… I mean raid 0. Got ahead of my self last night.
So long as you are good at
So long as you are good at backing up, I'd just add another 256 to the RAID-0. If your stripe size is lower, you will see a nice boost to QD1 sequentials that are larger than the stripe size (since those transfers are split across multiple drives). You're good for up to 6 SSDs in RAID on that board. While you'll hit the DMI throughput limit at ~4 SATA devices, there are still advantages to splitting your IOs across additional SSDs – even when they are bottlenecked.
I appreciate it. It all
I appreciate it. It all started when I found a smoking deal years ago on two 256gb drives, and has grown from there. I guess another 256gb 850 pro is on the horizon. The more the merrier right!?
I have a FreeNAS for redundancy and a WD Blue 2tb drive in my system as well for the important stuff. I am pretty sure my ISP hates when I re-install windows yearly and re-download my whole steam library though. 😀
You have multiple drives and
You have multiple drives and you redownload your Steam library upon Windows installation? That’s just irresponsible.
On page “https://www.pcper.com/reviews/Storage/Samsung-860-EVO-and-PRO-SATA-SSD-Review-512GB-1TB-and-4TB-Tested/Performance-Focus-0” at the end of the page you guys wrote “Being a PRO series SSD, the 2TB unit contains only MLC flash and no SLC cache.”.
The one being tested on that page is the 4TB version, there is no 2TB version being tested/shown.
So there will be 4TB M.2
So there will be 4TB M.2 variants? How long until we see a 4TB PCI-e M.2 from Samsung?
It’s down to PCB space. Not
It’s down to PCB space. Not enough room on M.2. Less room on mSATA.
I was wondering, with older
I was wondering, with older platform such as dual Xeon socket 2011 (v1) if there would be M.2 versions of these, would they function via an adapter?
I guess it would also be a general question on older platforms with NVME SSD or even Optain functioning or should I consider upgrade time to Threadripper/Ryzen?
Granted M.2 versions of these
Granted M.2 versions of these drives are not NVME, but a chance to remove cables would be a nice positive. Hence question stands for PCIE to M.2 adapters on older platforms for SATA/NVME/Optain
You’d have to use an M.2 to
You’d have to use an M.2 to SATA (not PCIe) adapter card.
The link at your article’s
The link at your article’s outset concerning the 850 line’s “silent migration to 64-layer V-NAND” actually links to your piece detailing the 850 EVO’s transition from 32- to 48-layer NAND. If a story exists about the switch to 64-layer NAND, I must have missed it.
In a similar vein, do you know if anyone has done testing to compare the 48-layer MLC/TLC versions of the 850 series drives to their 64-layer replacements?
It would be interesting to find out if the mixed workload performance and TRIM issues exhibited by the newly released 860 series were also present on the third revision of the 850 series, possibly indicating a limitation of the denser NAND rather than a bug in the new controller or firmware.
Hey, just to make sure: you
Hey, just to make sure: you did all the benchmarks in an identical environment and there was no possible microcode/Windows update for Meltdown/Spectre in between the benchmarks for the old and new SSDs, right?
860 pro cant support
860 pro cant support Raid ability?????????
It’s been 8 months since the
It’s been 8 months since the review, do you know if the TRIM issue has been fixed?
I’m deciding between the 850 or 860 currently.
Allyn have they fixed the
Allyn have they fixed the TRIM issue?