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
vs 10LPE
vs 7LPP
vs 7LPP
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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  • theblitz707 - Wednesday, February 10, 2021 - link

    Dead by daylight too, its very demanding and you need a sdg865's gpu at least to have 60fps at high at all times, sdg855 is very good too just sometimes dip a bit below 60. And there is a gigantic visual difference between low and high
  • Unashamed_unoriginal_username_x86 - Monday, February 8, 2021 - link

    I don't think Andrei gets enough credit for his work here, he's put hours upon hours into methodical, detailed articles for a website that's been forced into sponsored posts to make ends meet. God freaking bless
  • Alistair - Monday, February 8, 2021 - link

    he always does the best, I'm eagerly awaiting the S21 review also
  • FunBunny2 - Monday, February 8, 2021 - link

    "God freaking bless"

    one might wonder where all that revenue goes? could it be the corner office Suits?
  • Spunjji - Monday, February 8, 2021 - link

    I don't think it's actually that much revenue TBH
  • tuxRoller - Monday, February 8, 2021 - link

    Ugh. I'm extremely curious as to how much of a deal slsi have qcom.
    The "dark horse" (in the west/outside China) huawei looks like they out did themselves. Damn good job
  • Fulljack - Monday, February 8, 2021 - link

    probably because 80% capacity of TSMC 5nm are reserved for Apple A14 and M1, so Qualcomm won't bother with that 20% anyway.
  • tuxRoller - Tuesday, February 9, 2021 - link

    20% for their top end socs might be about right.
    Last year, at least, they were already splitting their orders between fabs.
  • tkSteveFOX - Monday, February 8, 2021 - link

    As expected due to Sammy's inferior fab node it's almost pointless to upgrade your SD865/+ device if not for a slightly better camera experience, but is too highly debatable.
    As a owner of a Sony 1 II I am perfectly willing to skip this generation entirely and wait for TSMCs 5nm to become widely available to Qualcomm and most noticeably, wait to see what chip Huawei can produce end of year to replace Kirin (still thinking they will acquire MTK at some point this year)
  • tuxRoller - Tuesday, February 9, 2021 - link

    I thought there was talk of huawei selling their smartphone brands (mate & p, I think)? I recall huawei denying it but the source who made the claim apparently also made a previous claim regarding huawei, and which Huawei also denied, that turned out to be correct

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