New Samsung 980 SSD improves performance of 970 EVO, EVO Plus

The latest generation of mid-grade consumer NVMe storage from Samsung was released today – the new drive is simply dubbed “Samsung 980”, without any suffix. The review guide that Samsung provided to us compares the new reader to the last generation 970 EVO – we didn’t have a 970 EVO on hand, but we did have a 970 EVO Plus and a 970 Pro, so these are the readers of the previous generation that we’re going to compare the new 980 to today.

A TLC reader under another name

Samsung 980 SSD

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If you are not at 100% of your NAND storage conditions, the first thing we need to talk about is the cell level. 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 you prefer, enabled and disabled. An SLC NAND cell can thus 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.

Samsung calls the 980 a “three-bit MLC” SSD, which is the same as calling a red car “pink”. To justify this, the company relies on the fact that “M” stands for “Multi” – so in plain English, “three-bit MLC” might make sense, even if it’s utterly absurd in established SSD terminology. . From now on, we’ll call it what it is: TLC.

As the data density of NAND cells increases, their write speed and endurance decreases – it takes more time and effort to read or write any of the eight discrete voltage levels in a cell than it does to achieve or define a simple and unambiguous on / off. assess.

To some extent, this drawback can be overcome with parallelism: by dividing the same 1MB write between eight banks of NAND, you can achieve much lower latency and higher throughput than if the entire 1MB were to be written on one bank. This is the main reason why even in the same SSD model, larger capacity SSDs are almost always faster than smaller ones.

A larger and more dynamic SLC cache

To speed writes beyond that, you need a faster buffer, which you can achieve just by configuring part of your NAND as a faster, more enduring SLC. The physical medium doesn’t really have to be any different; your SSD controller just needs to know to handle it that way.

In earlier versions of Samsung SSDs, the SLC buffer area was fixed – but starting with the 960 EVO, Samsung controllers introduced what they call “smart” Turbowrite, which is a dynamic amount of SLC buffer configurable by the controller. himself. In the 960 EVO and 970 EVO, the “Smart” buffer was a subset of the total SLC cache – the 980 introduced a much larger one and, for the first time, entirely dynamic SLC cache.

This huge increase (3.5x to 5.5x) in the fast cache area means that relatively empty 980 SSDs can significantly outperform previous Samsung EVO models, delaying when a user “falls off the write cliff” for a long time. much longer. The impact of “falling off the cliff” is worse for small drives, but even with the 1TB model, that means cutting top speeds by three-quarters.

Samsung’s improvements here don’t remove the write cliff – if you write more than the maximum amount of SLC cache without giving the drive a few moments to breathe, performance will still drop. But the dramatically increased delay before it hits is a welcome change.

Performance

Samsung’s review guide pits the new 980 against the latest generation 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 mostly sits between the EVO Plus. and latest generation Pro.

The 970 Pro doesn’t use SLC cache at all, so it doesn’t fall off the same “write cliff” that the 980 ends up doing. In the longest test above, the 1MB random write, which we performed using fio rather than CrystalDiskMark like the others – this gives the 970 Pro a chance to start performing cleanly away from the 980 before the test is complete.

The 980 Pro is significantly faster than the 970 EVO Plus in random and sequential 1MB workloads, but the increase doesn’t really affect users who are suffering. When we move to 4K workloads, there is hardly a choice between any of these drives.

In other words, when your reader makes big numbers to make you happy, the 980 makes them bigger and happier than its predecessor. But if you hope that a new hard drive will fix your slow copying issues, you’re probably out of luck – the 980 is no worse or better than other recent Samsung NVMe drives.

Price

The MSRP of the Samsung 980 has taken a downward turn, probably in large part due to its DRAM-free (and therefore less expensive to manufacture) design.

At the time of publication, actual retail prices for the Samsung 970 EVO Plus are $ 60, $ 80, and $ 160 for its 250GB, 500GB, and 1TB models. We have yet to see real-world price on the Samsung 980, but its MSRP is considerably lower – especially for the larger model – at $ 50, $ 70, and $ 130 respectively.

The steep price drop on the 1TB model makes the “buy big” argument even stronger. Even if you have little data, larger drives are faster, have higher write endurance, 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 more than 5 years.

Conclusions

Samsung’s new 980 is a good average quality consumer player. With dramatically increased SLC write buffer area, it can deliver higher performance more consistently and for 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 at a time, you should always be looking to spend more on a design that doesn’t rely on SLC cache first. location. But most consumers, including gamers, won’t fall into this category.

On the flip side, size continues to matter – the bigger the SSD you buy, the more write endurance and faster cache you get with increasing capacity. Even if you only have 200GB of data, the extra power that comes with a 1TB SSD is well worth the extra cost.

Good

• Extended performance that is more consistent than the 970 EVO Plus
• Maximum performance superior to the 970 EVO Plus
• Lower cost than 970 EVO Plus makes bigger SSDs more affordable
• Updated thermal design for increased reliability

The bad

• Constantly evolving consumer brand image: EVO, EVO Plus, non-EVO, Pro. We are waiting for “Samsung 9000 Blackwatch Plaid”
• Stop trying to make “three-bit MLC”, Samsung!

The ugly one