5nm / 5LPE: What do we know?

Starting off with the biggest new change of this generation, both the Snapdragon 888 and the Exynos 2100 are manufactured on Samsung’s new 5nm process node, which is the biggest unknown in today’s comparison.

What’s important to remember is that although Samsung calls this node 5nm, its design and characteristics are more similar to that of their 7nm node. Key new characteristics of the new node here are the reintroduction of single diffusion breaks (SDB) on an EUV process node, as well as slight changes in the cell libraries of the process.

Advertised PPA Improvements of New Process Technologies
Data announced by companies during conference calls, press briefings and in press releases
  7LPP
vs 10LPE
6LPP
vs 7LPP
5LPE
vs 7LPP
3GAE
vs 7LPP
Power 50% lower 20% 50%
Performance 20% ? 10% 35%
Area Reduction 40% ~9% <20% 40%

Per Samsung’s own numbers, the foundry claims that 5LPE is either 20% lower power than 7LPP, or 10% more performance. These are actually quite important figures to put into context, particularly when we’re comparing designs which are manufactured on TSMC’s process nodes.

In least year’s review of the Galaxy S20 series and the Exynos 990 and Snapdragon 865 SoCs, an important data-point that put things into context was Qualcomm’s Snapdragon 765 SoC which was also manufactured on Samsung’s 7LPP node, and featuring Cortex-A76 cores. In that comparison we saw that The Exynos 990 and the Snapdragon 765’s A76 cores behaves very similarly in terms of power consumption, however they fell behind TSMC-based Cortex-A76 cores by anywhere from 20% to 30%.

In that context, Samsung’s 5LPE process node improving power by 20% would mean they’d only be catching up with TSMC’s 7nm nodes.

Cortex A55 @ 1.8GHz - SPEC2006 456.hmmer Power

An interesting comparison to make – and probably one of the rare ones we’re actually able to achieve today, is the comparison between the Cortex-A55 cores inside of both the Snapdragon 865 and the new Snapdragon 888. Both SoCs feature the same IP cores, clock them at the same 1.8GHz frequency, and both feature the same amount of L2 cache, with their only real difference being their process nodes.

Using SPEC’s 456.hmmer – because it’s a workload that primarily resides in the lower cache hierarchies and thus, we avoid any impact of the possibly different memory subsystem, we can see that both SoCs’ power consumption indeed is almost identical, with performance also being identical with a score of 6.84 versus 6.81 in favour of the new Snapdragon 888.

So at least at first glance, our theory that Samsung’s 5LPE merely just catches up with the power consumption and power efficiency of TSMC’s N7/N7P nodes seems to be valid – at least at these frequencies.

Further interesting data is the voltage curves of the CPUs on the Exynos 2100. I’ve extracted the frequency voltages tables of both my devices, a regular S21 and an S21 Ultra, with the above curves being the better binned chip inside of the smaller S21.

Generationally, Samsung seems to have been able to greatly reduce voltages this generation. On the Cortex-A55 cores, the cores now only require 800mV at 2GHz whilst the Exynos 990 last year in our review unit they required over 1050mV. Similarly, although the comparison isn’t apples-to-apples, the Cortex-A78 cores at 2.5GHz only require 862mV, while the Cortex-A76 cores of the previous generation required also 1050mV.

What’s also very interesting to see is the voltage curves of the Cortex-X1 cores versus the Cortex-A78 cores: they’re both nigh identical to each other, which actually lines up with Arm’s claims that the new X1 cores have the same frequency capabilities as the A78 cores, only being larger and increasing their power consumption linearly in relation to their frequency.

Samsung’s frequency tables indicate that they had been testing the A55 up to 2.6GHz, and the X1 and A78 cores up to 3.2GHz – however voltages here are quite higher and it’s also likely SLSI wouldn’t have been able to achieve similar chip yields.

Unfortunately, I wasn’t able to extract data from my Snapdragon 888 S21 Ultra, so I can’t tell exactly where it falls in terms of voltages compared to the Exynos 2100. One thing I can confirm as being quite different between the two SoCs is that Samsung does actually give the Exynos 2100’s Cortex-X1 core its own dedicated voltage rail and PMIC regulator, while the Snapdragon 888 shares the same voltage rail across the X1 and A78 cores. In theory, that could mean that in more mixed-thread workloads, the Exynos has the opportunity to be more power efficiency than the Snapdragon 888.

Generally, the one thing I want people to take away here is that although Samsung calls this their 5nm node, it’s quite certain that it will not perform the same as TSMC’s 5nm node. Usually we don’t care about density all too much, however performance and power efficiency are critical aspects that effect the silicon and the end-products’ experiences.

The Snapdragon 888 & Exynos 2100 Memory Subsystem & Latency: Quite Different
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  • geoxile - Monday, February 8, 2021 - link

    What are you smoking? https://www.tomshardware.com/news/iphone-6s-a9-sam... the Samsung 14nm made A9s had a 10% advantage. Reply
  • Spunjji - Monday, February 8, 2021 - link

    Yeah, I think a lot of us had suspicions that was the case, but this is really confirming it. Interesting implications for Nvidia's next gen. Reply
  • yeeeeman - Monday, February 8, 2021 - link

    Crap, pure crap samsung. Qcom can do better on the same node with the same CPU IP. Pathetic. And people are still enthusiastic about rdna chip from samsung. If this is hot with Mali, then the one with rdna will be a toaster. Reply
  • lmcd - Monday, February 8, 2021 - link

    Honestly, this chip is probably on the rushed side. There was probably some work sunk into switching from the mongoose-series cores. I think Samsung will improve next generation substantially. I'm not surprised this generation they did not match Qualcomm, though I'm a bit surprised it's quite so decisive. Reply
  • yeeeeman - Monday, February 8, 2021 - link

    Yes, most certainly that is true. Also, it seems like the node is holding them up quite a lot also and I think the thermal characteristics of the Samsung process vs TSMC are worse since both the SD888 and Exynos exhibit very bad behavior in regards to this. The previous SD865 is much better in this regard with TSMC 7nm even though that chip is also quite pushed to its limits.
    Basically, process is critical. Anyone can say whatever it wants, but process tech is critical for failure or success. We have so many examples in the industry that show this. Intel with its 14nm vs AMD with 7nm TSMC. AMD could not have done the things they have with GF12nm. That is absolutely certain. Nvidia has just moved to Samsung 8nm from TSMC 12nm and ... it shows. The new cards are hot and power hogs. Samsung needs to invest lots of R&D in their fabs because their customers have given them a leap of faith this time and if they feel they lose too much with it, they will avoid samsung in the future.
    Reply
  • Exynos_is_weak - Monday, February 8, 2021 - link

    Lmao this is the exact same statement made by Samsung fans every single year and we know how it turned out. Oh "Exynos 990 will be revolutionary" or "Exynos 9825 will kick ass" and so on and so for. Now they are hedging their bets on AMD GPUs. And when that's subpar, they will fabricate another pathetic excuse. Come on aren't you guys tired of blindly defending Samsung? Reply
  • anad0commenter - Monday, February 8, 2021 - link

    Personally, I will keep hoping "the next Exynos is the one!" because I don't have a choice. In Europe it's only exynos and no snapdragon in their phones. Reply
  • Wereweeb - Monday, February 8, 2021 - link

    Why not buy an Oneplus phone then? Reply
  • druzzyaka - Monday, February 8, 2021 - link

    Because of OneUI.
    Thats why I bought HongKong version of S10. This phone still feels premium, despite being 2 year old.
    Reply
  • s.yu - Tuesday, February 9, 2021 - link

    I agree, currently on a Vivo, and noticed that OneUI is much better. Reply

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