The Samsung 860 QVO (1TB, 4TB) SSD Review: First Consumer SATA QLC
by Billy Tallis on November 27, 2018 11:20 AM 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 860 QVO is generally competitive with mainstream TLC SATA SSDs and is well ahead of the DRAMless Toshiba TR200. The 1TB 860 QVO's score is a bit lower when the drive isn't full because of the timing of the tests: the drive was still flushing the SLC cache in the background when the read test started.
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. This test is run twice: once with the drive prepared by sequentially writing the test data, and again after the random write test has mixed things up, causing fragmentation inside the SSD that isn't visible to the OS. These two scores represent the two extremes of how the drive would perform under real-world usage, where wear leveling and modifications to some existing data will create some internal fragmentation that degrades performance, but usually not to the extent shown here.
On the longer sequential read test, the 860 QVO continues to get reasonably close to the SATA speed limit when reading data that is contiguous on the flash itself. Where internal fragmentation is caused by writing to the drive randomly, the QVO's read speed suffers much more than for the TLC drives, and the 1TB 860 QVO ends up slightly slower than a mechanical hard drive.
Power Efficiency in MB/s/W | Average Power in W |
The power efficiency of the 860 QVO is only a little bit lower than the TLC drives for the contiguous data case. When dealing with fragmented data, the QVO is slightly more efficient than the Intel/Micron NVMe QLC drives despite being a bit slower.
The queue depth scaling behavior for the 860 QVO is very typical, with QD1 not quite saturating the SATA link but all higher queue depths hitting close to full speed. The one exception is a slight decrease from the 1TB drive during the final QD32 phase.
Aside from the mild QD32 drop in performance, the sequential read behavior of the 860 QVO doesn't fall outside the normal ranges we've come to expect from TLC drives.
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 Samsung 860 QVO handles the burst sequential write test fine when the drive is mostly empty and there's plenty of room in the SLC cache. When the drive is full, the 1TB model's speed suffers somewhat, but is still much faster than the mechanical hard drive or the DRAMless TLC drive.
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 SLC cache of the 1TB 860 QVO is not quite enough even when the drive is mostly empty, so it ends up in last place. The 4TB model's SLC cache keeps up with this test and it is as fast as any SATA drive.
Power Efficiency in MB/s/W | Average Power in W |
The 860 QVO is a bit more power-hungry than the 860 EVO, so the 4TB QVO only takes third place for efficiency among the SATA drives in this bunch. The 1TB QVO has similar efficiency to the faster but more power-hungry 1TB QLC NVMe drives from Intel and Micron.
The 1TB 860 QVO is mostly slow and steady during the sequential write test, while the 4TB model's performance is as good as any other SATA drive.
The 1TB 860 QVO's sequential write behavior sticks out clearly as far slower than typical, but it's not unprecedented: there have been TLC drives this slow, but most of them were much smaller than 1TB. The 4TB model blends in with the crowd much better.
109 Comments
View All Comments
CheapSushi - Wednesday, November 28, 2018 - link
Yeah the premise was cheaper NAND for bulk storage with compromises. That way all okay in my mind. But as shown, there's just no good value proposition here yet. Just inherently I figured QLC would be 33% cheaper than TLC and then mass production and the higher density stacking would bring that down further. But...I guess not.nagi603 - Friday, November 30, 2018 - link
At $400 I'd toss out all the current HDDs of my NAS. Maybe in a few years.... or not, as the HDD prices/capacities move too.azazel1024 - Friday, November 30, 2018 - link
My price point is roughly 8 cents a GB and performance of at least 250MB/sec sustained writes/reads.Which these aren't at. That might mean a few more generations of TLC drives to get there. I don't know. My use case is replacing the spinning rust in my desktop and server. I mirror storage between them and I am running dual 1GbE interfaces with SMB Multichannel. So I can push about 235MB/sec across.
Sometimes I am just shoving a few GB file (sometimes one or two single digit MB sized files, but more often larger ones). On rare occasions I am backing up completely from one machine to the other, because reasons. So when tossing 2-3TB of data, I don't need my transfer "stalling" at 80MB/sec, or even 160MB/sec. Hopefully soon networking prices on 2.5/5/10GbE will drop enough I will upgrade there. I don't necessarily need to saturate a 2.5GbE, let alone 5 or 10GbE interface with big transfers.
So my benchmark is 250MB/sec sustained on full disk transfers. That way I don't need to set up drives in RAID to accommodate higher speeds. As one of things I am looking forward to/hoping for with SSDs is being able to move to storage pools/JBOD type setup so that as I start pushing my capacity limits, I can just add a new drive, rather than needing to replace an entire array. And those sustained speeds better be able to manage that with the disk 80-90% full. One of those things that makes me shy away from using HDD arrays that full is the performance suffers a lot once you start getting that far in on the tracks (my current 2x3TB RAID0 arrays can push about 320MB/sec when on the outer tracks, on the inner ones it is only about 190MB/sec).
Once of these days I could justify dishing out $600-800 to replace my 2x3TB arrays with 5-6TB of storage in each machine. Especially if it is storage that I can potentially keep using for a long time (I don't know, call it a decade or so) by just adding a new disk once capacity starts getting low, rather than replacing all of them. But I need/want good performance while I am at it.
For my server I can still comfortably live with a 60GB system drive. When I upgrade it, I will likely FINALLY replace the old SATAII SSD in there with a newer SATAIII 120GB SSD or get an M.2 120GB depending on what the board will support. Basically the smallest capacity I can get. It doesn't need heaps of performance. My desktop I will likely get a 500GB M.2 TLC drive once I finally upgrade it (currently running a last generation 256GB TLC SATAIII drive as the system disk).There I'd like some nice performance, but frankly a good M.2 TLC drive with 512GB is big enough jump in performance I don't care to spend the money on an MLC drive for the system disk.
TheCurve - Tuesday, November 27, 2018 - link
Another great review from Billy. Love reading your stuff!rocky12345 - Tuesday, November 27, 2018 - link
This is great and a step closer to getting rid of spinning drives but they are not there yet. The prices of these Samsung drives are far better at the 4TB range but I just picked up a 4TB WD Blue for $99 Canadian on the black Friday sales granted that same drive before the sale was $209.99 Canadian but even still far cheaper than the $599.99US for the Samsung 4TB almost SSD drive.With all of that said I am very happy to see large TB drives for SSD coming into a lower price range probably going to be another 5-6 years before the prices match for spinning and SSD drives or if Seagate and WD totally stop making spinning drives then of coarse we have nothing to fall back on if we want large TB hard drives in our systems for data storage and we will have to pay the price of these types of SSD drives.
On a side note my fear is that when Seagate and WD stop making spinning drives SSD drive prices might sky rocket because we have no other option. The only reason SSD drives are coming down in the larger sizes is these companies are trying to compete with large TB spinning drives on price points.
kpb321 - Tuesday, November 27, 2018 - link
I'm not sure SSD's will ever pass up HD's for $ per GB for pure bulk storage. Even the "Cheap" 4tb SSD is around the cost of 2x 10 TB HDs so somewhere around 5X more expensive in $ per GB. Not an impossible margin but still a lot of ground to make up vs a moving target. What has happened is SSDs have gotten "big enough" and "cheap enough" that for many people they are viable as the only drive in their machine. Looking at Newegg it's ~$45 for your basic 1tb hd and you can pick up a cheap ~250gb SSD for a little less or a ~512gb SSD for a little more. I'd certainly prefer a 250 or 512 gb SSD as the drive in my system over a 1tb HD but if you do need bulk storage (1tb+) HDs are still hard to beat. 3TB hd's start off at ~$85 and continue to be more cost effect at higher sizes so I don't think HDs will completely vanish. They may become increasingly specialized to bulk storage and cloud providers with things like SMR trading off some performance for increased density but I doubt they will go away. Cheap PC mfgs do still seem to like the cheap 1tb hds. About the same cost as a small but usable SSD but give big numbers for the ads.dontlistentome - Tuesday, November 27, 2018 - link
It's about 10 years ago that I bought an Intel 80GB drive for $250. We're getting 2TB flash for that now - about a factor of 25 times reduction in price.Another 5 times cheaper? Easy.
DanNeely - Tuesday, November 27, 2018 - link
For comparison, in 2008 the biggest HDDs were apparently 1.5TB in size; that drive launched at ~$215 (although it rapidly dropped afterward). For comparison a 14TB Ironwolf is $530 at B&H. That's 9.3x more capacity at at 2.4x the price; or roughly at 3.8x improvement in price per TB at the top end. Or only 2.7x is you use the ~$150 price estimated price for nov 08.Flash might end up needing to drop 10x in price per TB to beat spinning rust; but it has momentum behind it, and the more market share it wins based on size/power/performance the more economies of scale and larger R&D budgets will tilt the floor in its favor.
https://www.tomshardware.com/reviews/hdd-terabyte-...
https://camelcamelcamel.com/Seagate-Barracuda-7200...
Lolimaster - Thursday, November 29, 2018 - link
Ever heard of law of diminishing returns?At 1st tech is hard to produce and sell than it scales till you reach a wall, same with flash cards at the times of N64, 32-64MB for $100.
Even HDD's which a well known tech is having a hard time executing the next step, HAMR which should boost capacities to 20-50TB, 4 years of delay.
The_Assimilator - Thursday, November 29, 2018 - link
Just like HDDs never passed tapes in cost/GB for bulk storage.