Samsung PM981 NVMe SSD Review

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There are a few angles to examine with the Samsung PM981. The PM981 is an OEM SSD designed to meet requirements set by a third party. In this case, it's the large system builders that define the parameters. Many of the companies have adapter M.2 SSDs for notebooks where thinner, lighter, flashier, and faster sells new products in a congested market. That's where Samsung aimed the PM981, and if you plan to buy a notebook in the next year, this product should be interesting to you.

Judging from our previous experiences, we can also use the PM981 as an early look at what Samsung may bring to the retail market soon. This is a bit more interesting because we always covet what we can't have. The next generation Samsung retail NVMe SSD is still, at the very least, a few months away.

The market has changed since we were in this same position with the SM961 and PM961. You could actually order those OEM drives, but Samsung slammed many of those doors shut. The SM961 was a high-performance model that outperformed the retail 950 Pro, but at a lower price. The OEM drive also provided twice the capacity of Samsung's retail drive, and for many enthusiasts that was enough to place an order.

None of those advantages apply today. Samsung will have a tough time getting enthusiasts excited about a new TLC SSD. Many of us dread the day when our only options are either TLC and QLC SSDs. For the foreseeable future, 3D XPoint will captivate the enthusiast audience. Unfortunately, we don't see Samsung releasing a Z-NAND equivalent for the desktop anytime soon, although we welcome the idea.

The PM981 OEM-focused NVMe SSD doesn't introduce better performance or higher capacities than SSDs you can buy now. The retail version could easily scale well past 1TB. The South Korean company has a new fab in China and 512Gbit NAND on the roadmap. Samsung will have room for four NAND packages on the M.2 2280 form factor if it goes back to a PoP controller and DRAM. That would give us something we could easily get very excited about: the first 4TB consumer M.2 SSD. The PM981’s performance will also increase with the wave of Samsung's magic NVMe driver wand. The next revision will undoubtedly include optimizations for the new Phoenix controller.

Our article is more of an exhibition than a review of the PM981. Currently, we don't have a datasheet or additional information. We're basically flying at night with a flashlight.

We did learn quite a bit about the new architecture and how Samsung improved on the previous generation. Mixed workloads received the biggest performance increase, which benefits the multi-taskers among us. Low-QD random read performance also increased roughly 2,000 IOPS, which is great for responsiveness.

The PM981's biggest drawback is TLC NAND, and as a result, sustained write performance took a step back. The PM981 512GB's high-speed buffer only absorbs around 25GB of data, and sequential performance drops when the workload spills over to native TLC NAND. The 1TB model has a bigger 50GB buffer that can absorb a full Blu-Ray ISO, which we consider the benchmark for an acceptable amount of cache. The 1TB's performance drop-off is also much less severe.

We haven't found a reliable source with a lot of drives, so our drives came from a small reseller. We spent roughly $400 for the PM981 1TB and $200 for the 512GB. The drives came from Asia, so shipping added another $100. The seller had plenty of 512GB drives when we placed our order, but we had to wait a week for the 1TB model. Given the hassles, cost, and lack of exciting features like record-setting performance or higher capacities, we don't recommend the PM981 as an aftermarket option.

Most of the big box brands don't give shoppers the option to choose individual system components. If we had the option, we can't think of a reason to pass over the PM981 if an MLC drive isn't available. If you want long battery life with solid performance, the PM981 is the best TLC option we've tested to date. That's something we can get excited about.


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Chris Ramseyer
Chris Ramseyer is a Contributing Editor for Tom's Hardware US. He tests and reviews consumer storage.
  • kiniku
    "The PM981's biggest drawback is TLC NAND, and as a result, sustained write performance took a step back." For most high-end gamers this won't be a factor unless you are writing multi-GBs of data back at a time back to the SSD. Which is why most gamers are throwing money away buying the "PRO" version of Samsung's NVE SSDs.
  • dgpadia
    Here's a question. I have a Lenovo Thinkpad Yoga 15, 20DQ Series. 200 or so SSD. Would I want to upgrade to this? Would absolutely kill my battery? If so, is there a better option. Let's assume reasonable budget (no more than $600-700, tops)
  • doesitmatter
    There's an error on page 2 in the Sequential Write Performance charts. The bar chart for QD2 128k write for the 960 Pro 1tb doesn't agree with what the line graph says. The bar chart shows it at 1544MB/s (exact same as the PM981), but the line graph shows it somewhere between 2100MB/s and 2200 MB/s, which should make it the top performer on the bar chart.
  • gasaraki
    Not impressed.
  • mapesdhs
    Why are PCMark 8 tests still included? They've never shown statistically meaningful or useful differences between products. The variation in results is miniscule.
  • AgentLozen
    GASARAKI said:
    Not impressed.

    Hey! Thanks for the comment Gasaraki! Short, sweet, and to the point. I was sort of curious as to WHY you weren't impressed. You sort of left me hanging, but that's alright.

    I think there's a lot to be excited about with the PM981. There are also a few disappointments.

    I really liked the mixed work load performance. At low queue depth, the PM981 performed exceptionally well. Also, the battery life was a nice improvement over Samsung's last generation TLC drive (the 960 EVO).

    With that said, I think the most interesting comparison to make is between the 960 PRO and the PM981. There were a number of sequential and random benchmarks where the PM981 wasn't as good a performer. I expected some inadequacies between MLC and TLC flash, but even the 960 EVO (with TLC flash) was beating it. The article states that the 64 layer flash being used in the PM981 was supposed to be faster and more power efficient. Is it a problem with the Phoenix controller? The author of the article claims that the culprit was probably thermal throttling.

    Personally, the news I'm most happy to see is the pricing. I know $400 for 1TB probably doesn't reflect the final price of the consumer Samsung 980 drive due out in a few months, but if we could get this level of performance for $.40 per GB, that would be really terrific.

    Edit: Typo and clarification
  • Green_4
    Can you please inclunde in this charts Intel Optane SSD 900p ....,5292-2.html
  • Brian_R170
    20432954 said:
    Why are PCMark 8 tests still included? They've never shown statistically meaningful or useful differences between products. The variation in results is miniscule.

    They pretty much show that the difference between the best and the worst SSD is hardly noticeable to most users.

    Reviewers have found ways to use real applications to show CPU and GPU performance, but all of the SSD tests that are "meaningful" are synthetic and therefor, not actually meaningful. I liken most of the synthetic SSD benchmark data to automobile reviews that tout a vehicle's top speed. It's cool data, but not useful to nearly any owner.
  • CRamseyer
    If you know what you are looking at all of the tests from PCMark 8 on have meaning for most of our readers. Please see the How We Test SSDs and HDDs article for details.
  • gaaah
    I need more room in my pants.