Jim Salter
Samsung’s newest generation of midgrade consumer NVMe storage has been launched – the new drive is simply nicknamed “Samsung 980”, with no suffix. The reviewer’s guide that Samsung provided us compares the new unit to the latest generation 970 EVO – we didn’t have a 970 EVO available, but we did have a 970 EVO Plus and a 970 Pro, so these are the units from the previous generation that we ‘ I will compare the new 980 with today’s.
A TLC drive with any other name
Samsung 980 SSD
If you are not 100% satisfied with your NAND storage terms, the first thing we need to talk about is cell levels. The fastest and most durable NAND storage is the SLC – the single-level cell. An SLC NAND cell has only two values - 0 and 1 or, if you prefer, activated and deactivated. An SLC NAND cell can therefore store a single bit of data. From there, we have the MLC that can store two bits, the TLC that can store three bits and the QLC that can store four bits of data per cell.
| Designation | bits per cell | Discrete voltage levels |
| SLC | 1 bit | two |
| MLC | 2 bits | 4 |
| TLC | 3 bits | 8 |
| QLC | 4 bits | 16 |
Samsung calls the 980 SSD a “three-bit MLC”, which is a lot like referring to a red car as “pink”. To justify this, the company relies on the fact that “M” stands for “Multi” – so, in simple language, “three-bit MLC” could make sense, despite being totally absurd in the established SSD terminology. From now on, we will call it what it is: TLC.
As the data density of NAND cells increases, their recording speed and resistance decrease – it takes more time and effort to read or write one of eight discrete voltage levels in a cell than to obtain or define a simple, unambiguous on / off value.
To some extent, this disadvantage can be overcome with parallelism – by dividing the same 1 MiB recording between eight NAND banks, you can achieve much lower latency and higher throughput than you would if the entire 1 MiB had to be recorded on one single bank. This is the main reason why, even within the same SSD model, higher capacity SSDs are almost always faster than smaller ones.
A larger, more dynamic SLC cache
In addition to speeding up recordings, you need a faster buffer area – which can be achieved by simply configuring part of your NAND as the fastest moving and highest resistance SLC. The physical media really doesn’t have to be different; your SSD controller simply needs to know how to handle 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 they call the “Intelligent” Turbowrite, which is a dynamic amount of SLC buffer configurable by the controller itself. In the 960 EVO and 970 EVO, the “smart” buffer area was a subset of the total SLC cache – the 980 has a much larger cache and, for the first time, fully dynamic SLC cache.
| Capacity | 970 EVO | 980 | ||||
| Full SLC cache | Static SLC cache | Dynamic SLC cache | Full SLC cache | Static SLC cache | Dynamic SLC cache | |
| 250 GB | 13 GB | 4GB | 9GB | 45GB | 0GB | 45GB |
| 500 GB | 22 GB | 4GB | 18 GB | 122 GB | 0GB | 122 GB |
| 1 TB | 42 GB | 6 GB | 36 GB | 160 GB | 0GB | 160 GB |
This huge increase (3.5x to 5.5x) in the fast cache area means that 980 relatively empty SSDs can significantly outperform previous Samsung EVO models, delaying the point where a user “falls off the recording cliff” for much more time. The impact of “falling off the cliff” is worse for smaller drives – but even with the 1TB model, that means reducing top speeds by up to three-quarters.
Samsung’s improvements here do not narrow the recording gap – if you record more than the maximum amount of SLC cache without giving the unit a few moments to breathe, performance will still drop. But the much longer delay before arriving is a welcome change.
Performance
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All of the tests in this chart are with a block size of 1 MiB – this is a performance similar to what you would get by reading or writing very large single files.
Jim Salter
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These 4 KiB block size graphics demonstrate the worst performance of the drives – reading or writing many, many tiny files.
Jim Salter
Samsung’s reviewer’s guide shows the new 980 against the latest generation 970 EVO. Unfortunately, we didn’t have a 1 TB 970 EVO available – but we did have a 1 TB 970 EVO Plus and a 1 TB 970 Pro. Unsurprisingly, the new 980 is mostly between the EVO Plus and the next generation Pro.
The 970 Pro does not use an SLC cache and therefore does not fall off the same “recording cliff” that the 980 eventually does. In the longest run test above – the 1 MiB random recording, which we performed using fio instead of CrystalDiskMark like the others – this gives the 970 Pro a chance to start running smoothly from the 980 before the end of the test.
The 980 Pro is significantly faster than the 970 EVO Plus in random, sequential 1 MiB block-size workloads – but the increase is not really aimed at users where the pain lives. When it comes down to 4 KiB workloads, there is little to choose between any of these units.
In other words, when your unit is making huge numbers to make you happy, the 980 makes them bigger and happier than their predecessor. But if you expect a new legal unit to fix your slow copy problems, you’re probably out of luck – the 980 is neither worse nor better than other recent Samsung NVMe units.
Price
The MSRP on the Samsung 980 has dropped sharply, probably due in large part to its DRAM-free design (and therefore less expensive to manufacture).
At the time of publication, retail prices in the real world on the Samsung 970 EVO Plus are $ 60, $ 80 and $ 160 for its 250 GB, 500 GB and 1 TB models. We haven’t seen the actual prices for the Samsung 980 yet, but its MSRP is considerably lower – especially for the larger model – at $ 50, $ 70 and $ 130, respectively.
The huge drop in the price of the 1 TB model makes the argument for “buying big” even stronger. Even if you have little data, larger units are faster, have greater recording resistance and more consistent performance. The $ 80 price difference between a 250 GB Samsung 980 and its 1 TB older brother is a worthwhile investment – especially if you want to use the same drive with maximum performance for more than 5 years.
Conclusions
Samsung’s new 980 is an excellent drive for the midgrade consumer. With a dramatically increased SLC recording buffer area, it can provide high performance more consistently and for longer than previous generations. It’s not a Pro-level drive yet – if you write tons of data to your SSD for long periods at a time, you should spend more on a design that doesn’t depend on the SLC cache in the first place. But most consumers – including players – will not fall into this category.
On the other hand, size continues to matter – the bigger the SSD you buy, the more write resistance and fast caching you get with increasing capacity. Even if you only have 200 GiB of data, the extra muscle that comes with a 1 TB SSD is worth the additional cost.
The good
- More consistent extended performance than 970 EVO Plus
- Maximum performance greater than 970 EVO Plus
- Cost less than 970 EVO Plus makes larger SSDs more affordable
- Updated thermal design for greater reliability
The evil
- Changing consumer brand – EVO, EVO Plus, not EVO, Pro. We are waiting for the “Samsung 9000 Blackwatch Plaid”
- Stop trying to make “three-bit MLC” happen, Samsung!