The Samsung 860 QVO SSD is an excellent everyday artist and a great bargain in its 2TB and 4TB flavors. It's also the second level 4 (4-bit) SSD to go through our portals. , the other being the Intel 660P SSD.
The reason I mentioned Intel's competitive strategy in the beginning is that it becomes clear that NAND 4-bit, while allowing greater capacity, also has an impact on the performance that providers must get around. How much does a provider assign to the 4-bit drive to purchase and determine if you are better off with a MLC or TLC?
Note: Samsung calls the 860 QVO the 4-bit MLC format. As the acronym MLC stands for "Multi-Level Cell", it is technically correct. However, most of them refer to this as a four-level cell or QLC, which I suppose Q stands for in QVO.
Design and features
The 860 QVO is a 6 Gbps SATA SSD of 7mm thickness. The gray color is lighter than that of most Samsung SSDs. It will be available in four capacities: 1TB, 2TB and 4TB. This last advantage is a boon to 4-bit NAND technology: a higher data density than the 3-bit CCM, so you can adjust more data in the same number of chips.
The drive provides 1 GB of DRAM cache for each 1 TB capacity. The TBW (TeraBytes Written) index is 360 TB for 1 TB of capacity. The 1 TB version I have tested has about 42 GB of secondary cache available (QLC, written as SLC or MLC). The 2 and 4 TB disks each get 78 GB of cache.
The price starts at $ 150 for the 1 TB drive. The 2 TB costs $ 300 and the 4 TB model costs $ 600. A 4TB SSD drive at 500 US dollars is very economical compared to anything on the market, as well as what you would have paid only last year.
In fact, writing more bits in a NAND cell takes longer. SLC NAND cells are not so much faster than TLC or QLC cells; writing a single bit is faster. Do not write that one bit in TLC or QLC, and they are almost as fast. Write three or four bits and they are not even close. Therefore, a certain amount of the TLC (or QLC in this case) of any SSD is treated as SLC or MLC to form a secondary cache.
By using this secondary cache – again, about 42 GB – the 860 QVO has proven very powerful in most cases, as you can see from the results below. There was no slowdown in performance until our 48 GB file copy tests, in which the last 4 GB was at 70 Mbps. This would not happen in 2TB or 4TB disks, with their level 2 cache more abundant.
AS SSD 2.0 had about the same opinion as CrystalDiskMark about the speed of the 860 QVO. Note that this test is not as optimistic about the bitrate, it will be slightly wrong on the lower side of what we see in our 48 GB real copy tests.
The search times, as shown below, are actually quite fast compared to most 6Gbps SATA SSDs. This may have something to do with the generous and previously described allotment of the DRAM cache.
You can see below that the copy tests were only slightly affected by the exhaustion of the 860 QVO cache, but only because so little data was written in the main body of the QLC memory. Double that test size, and the 1TB 860 QVO and Kingston bars would have been much longer than those of Sony or Seagate. Even the 2TB and 4TB capacities would be dry in this scenario.
When the 860 QVO runs out of cache, it's pretty depressing. The drive clears the cache by writing the data into the main body of the 4-bit NAND, but this process takes a while. I waited a good ten minutes between tests. Below, you can see what happened when I did not wait so long to try to copy 48 GB again. The original 48GB copy did not slow down to around 90%.
For comparison, in terms of sustained throughput, we saw hard drives running at 250 Mbps. But even when writing slowly, SSDs retain their ultra-fast search times. Also note that it is strictly speaking. NAND read speeds in SATA SSDS remain fast, regardless of the number of bits read.
A good reader for the general public user
The 860 QVO is mostly an excellent SSD, but there are a number of cheaper one-ton competitors that do not slow down. On the other hand, 2TB and 4TB drives cost a few hundred dollars less than the competition and do not cache as quickly. This is a price difference important enough that I consider the compromise, which may be worthwhile to vary according to your needs.
Negotiate or not, know that you will see a massive performance drops when the drive runs out of cache. It does not run out often, but it's ugly when it does.