Jim Salter
Samsung’s latest generation of mid-grade NVMe consumer storage is out today – the new drive is simply called the “Samsung 980”, without any suffix. The review guide Samsung provided us compares the new drive to the previous generation’s 970 EVO – we didn’t have a 970 EVO on hand, but we did have a 970 EVO Plus and a 970 Pro, so those are the drives from the previous generation we’ I compare the new 980 with today.
A TLC disc with a different name
Samsung 980 SSD
If you’re not 100% aware of your NAND storage conditions, the first thing we need to talk about is cell levels. The fastest and most durable NAND storage is SLC: the Single Level Cell. An SLC NAND cell has only two values: 0 and 1, or, if desired, on and off. Thus, an SLC NAND cell can store a single bit of data. From there we have MLC which can store two bits, TLC which can store three and QLC which can store four bits of data per cell.
| Designation | bits per cell | Discreet Voltage Levels |
| SLC | 1 bit | 2 |
| MLC | 2 bit | 4 |
| TLC | 3 bit | 8 |
| QLC | 4 bit | 16 |
Samsung calls the 980 a “three bit MLC” SSD, which looks a lot like the “pink” of a red car. To justify this, the company relies on the fact that “M” stands for “Multi” – so in plain English “three bit MLC” might make sense, despite being utter nonsense in the established terminology of SSDs. From now on, we’re going to call it what it is: TLC.
As the data density of NAND cells increases, their speed and write time decrease – it takes more time and effort to read or write one of eight discrete voltage levels to a cell than it does to do a simple, unambiguous on/off button to get or set. where the.
To some extent, this drawback can be overcome with parallelism: by splitting the same 1MiB write between eight NAND banks, you can get much lower latency and higher throughput than if the entire 1MiB had to be written to a single bank. This is the main reason that even within the same SSD model, larger capacity SSDs are almost always faster than smaller ones.
A larger, more dynamic SLC cache
To further accelerate writing, you’ll need a faster buffer area, which you can easily get by configuring part of your NAND as a faster-moving, more durable SLC. The physical media doesn’t really have to be different; your SSD controller just needs to know to treat it that way.
In previous versions of Samsung SSDs, the SLC buffer area was fixed, but starting with the 960 EVO, Samsung controllers introduced what it calls “Intelligent” Turbowrite, which is a dynamic amount of SLC buffer that can be configured by the controller itself. In the 960 EVO and 970 EVO, the “intelligent” buffer area was a subset of the overall SLC cache – the 980 introduces a much larger and, for the first time, whole dynamic SLC cache.
| Capacity | 970 EVO | 980 | ||||
| Total SLC cache | Static SLC cache | Dynamic SLC cache | Total SLC cache | Static SLC cache | Dynamic SLC cache | |
| 250GB | 13GB | 4GB | 9GB | 45GB | 0GB | 45GB |
| 500GB | 22GB | 4GB | 18GB | 122GB | 0GB | 122GB |
| 1TB | 42GB | 6GB | 36GB | 160GB | 0GB | 160GB |
This massive (3.5x to 5.5x) increase in fast cache area means relatively empty 980 SSDs can significantly outperform previous Samsung EVO models, delaying the point at which a user “falls off the write cliff” for much longer. The impact of “falling off the cliff” is worse for smaller drives, but even with the 1TB model, that means top speeds are reduced by as much as three-quarters.
Samsung’s improvements here don’t make the writing cliff go away – if you write more than the maximum SLC cache value without giving the drive a moment to breathe, performance will still plummet. But the greatly increased delay before it hits is a welcome change.
Performance
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All the tests in this chart are at a block size of 1 MiB – this is a performance comparable to what you would get when reading or writing very large single files.
Jim Salter
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These 4KiB block size tables demonstrate the worst performance of the drives: reading or writing a lot of very small files.
Jim Salter
Samsung’s reviewer’s guide pits the new 980 against the previous generation’s 970 EVO. Unfortunately we didn’t have a 1TB 970 EVO on hand, but we did have a 1TB 970 EVO Plus and a 1TB 970 Pro. Unsurprisingly, the new 980 falls between the previous-generation EVO Plus and Pro for the most part.
The 970 Pro doesn’t use an SLC cache at all, so it doesn’t fall off the same “write cliff” that the 980 eventually does. In the longest running test above – the 1MiB random write, which we performed using fio instead of CrystalDiskMark like the others – this gives the 970 Pro a chance to run cleanly away from the 980 before the test ends.
The 980 is significantly faster than the 970 EVO Plus in both random and sequential 1MiB block size workloads, but the increase isn’t really aimed at users where the pain lives. When we go back to 4KiB workloads, there is little to choose from between these drives.
In other words, when your drive is making big numbers to make you happy, the 980 makes them bigger and happier than its predecessor. But if you’re hoping that a nice new disc will slowly copy problems, you’re probably out of luck: the 980 is no worse or better than other recent NVMe drives from Samsung.
Price
The MSRP on the Samsung 980 has taken a sharp turn, probably due in large part to its DRAM-less (and therefore less expensive manufacturing) design.
As of publishing time, real retail prices on Samsung 970 EVO Plus will run $60, $80, and $160 for the 250GB, 500GB, and 1TB models. We haven’t seen actual pricing for the Samsung 980 yet, but the MSRP is significantly lower, especially for the larger model, at $50, $70 and $130 respectively.
The big drop in price of the 1TB model makes the “buy big” argument even stronger. Even if you’re low on data, larger drives are faster, have higher write durability, and more consistent performance. The $80 price difference between a 250GB Samsung 980 and its 1TB big brother is a worthwhile investment, especially if you want to use the same drive at peak performance for over 5 years.
conclusions
The new 980 from Samsung is an excellent mid-range consumer drive. With a drastically larger SLC write buffer area, it can deliver more consistently high performance and longer than previous generations. It’s still not a Pro-level drive — if you’re writing tons of data to your SSD for long periods of time, you should still try to spend more on a design that doesn’t rely on SLC cache in the first place. But most consumers, including gamers, do not fall into this category.
On the other hand, size still matters: the larger the SSD you buy, the more write durability and fast cache you get with the larger capacity. Even if you only have 200GiB of data, the extra power that comes with a 1TB SSD is well worth the extra cost.
The good
- More consistent extended performance than the 970 EVO Plus
- Higher maximum performance than 970 EVO Plus
- Lower cost than the 970 EVO Plus makes larger SSDs more affordable
- Updated thermal design for increased reliability
The bad
- Ever-changing consumer branding: EVO, EVO Plus, non-EVO, Pro. We are waiting for “Samsung 9000 Blackwatch Plaid”
- Stop trying to make “three-bit MLC” happen, Samsung!