SPEC CPU - Single-Threaded Performance

SPEC2017 and SPEC2006 is a series of standardized tests used to probe the overall performance between different systems, different architectures, different microarchitectures, and setups. The code has to be compiled, and then the results can be submitted to an online database for comparison. It covers a range of integer and floating point workloads, and can be very optimized for each CPU, so it is important to check how the benchmarks are being compiled and run.

We run the tests in a harness built through Windows Subsystem for Linux, developed by our own Andrei Frumusanu. WSL has some odd quirks, with one test not running due to a WSL fixed stack size, but for like-for-like testing is good enough. SPEC2006 is deprecated in favor of 2017, but remains an interesting comparison point in our data. Because our scores aren’t official submissions, as per SPEC guidelines we have to declare them as internal estimates from our part.

For compilers, we use LLVM both for C/C++ and Fortan tests, and for Fortran we’re using the Flang compiler. The rationale of using LLVM over GCC is better cross-platform comparisons to platforms that have only have LLVM support and future articles where we’ll investigate this aspect more. We’re not considering closed-sourced compilers such as MSVC or ICC.

clang version 10.0.0
clang version 7.0.1 (ssh://git@github.com/flang-compiler/flang-driver.git
 24bd54da5c41af04838bbe7b68f830840d47fc03)

-Ofast -fomit-frame-pointer
-march=x86-64
-mtune=core-avx2
-mfma -mavx -mavx2

Our compiler flags are straightforward, with basic –Ofast and relevant ISA switches to allow for AVX2 instructions. We decided to build our SPEC binaries on AVX2, which puts a limit on Haswell as how old we can go before the testing will fall over. This also means we don’t have AVX512 binaries, primarily because in order to get the best performance, the AVX-512 intrinsic should be packed by a proper expert, as with our AVX-512 benchmark.

To note, the requirements for the SPEC licence state that any benchmark results from SPEC have to be labelled ‘estimated’ until they are verified on the SPEC website as a meaningful representation of the expected performance. This is most often done by the big companies and OEMs to showcase performance to customers, however is quite over the top for what we do as reviewers.

Single-threaded performance of TGL-H shouldn’t be drastically different from that of TGL-U, however there’s a few factors which can come into play and affect the results: The i9-11980HK TGL-H system has a 200MHz higher boost frequency compared to the i7-1185G7, and a single core now has access to up to 24MB of L3 instead of just 12MB.

SPECint2017 Rate-1 Estimated Scores

In SPECint2017, the one results which stands out the most if 502.gcc_r where the TGL-H processor lands in at +16% ahead of TGL-U, undoubtedly due to the increased L3 size of the new chip.

Generally speaking, the new TGL-H chip outperforms its brethren and AMD competitors in almost all tests.

SPECfp2017 Rate-1 Estimated Scores

In the SPECfp2017 suite, we also see general small improvements across the board. The 549.fotonik3d_r test sees a regression which is a bit odd, but I think is related to the LPDDR4 vs DDR4 discrepancy in the systems which I’ll get back to in the next page where we’ll see more multi-threaded results related to this.

SPEC2017 Rate-1 Estimated Total

From an overall single-threaded performance standpoint, the TGL-H i9-11980HK adds in around +3.5-7% on top of what we saw on the i7-1185G7, which lands it amongst the best performing systems – not only amongst laptop CPUs, but all CPUs. The performance lead against AMD’s strongest mobile CPU, the 5980HS is even a little higher than against the i7-1185G7, but loses out against AMD’s best desktop CPU, and of course Apple M1 CPU and SoC used in the latest Macbooks. This latter comparison is apples-to-apples in terms of compiler settings, and is impressive given it does it at around 1/3rd of the package power under single-threaded scenarios.

CPU Tests: Core-to-Core and Cache Latency SPEC CPU - Multi-Threaded Performance
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  • back2future - Tuesday, May 18, 2021 - link

    it's almost one could skip PCIe4 if early 2022 PCIe5 is stable on power management and performance expectations on mainboards? Reply
  • mode_13h - Thursday, May 20, 2021 - link

    > it's almost one could skip PCIe4 if early 2022 PCIe5 is stable ... on mainboards?

    Uh, I'm still eager to see exactly how Intel is going to use PCIe 5, in Alder Lake. I suspect it'll be used only for the DMI link to the chipset, in fact.

    Since graphics cards and M.2 SSDs aren't even close to maxing PCIe 4, I struggle to see why they would bother with the added cost and potential issues of supporting 5.
    Reply
  • heickelrrx - Monday, May 17, 2021 - link

    you can put 4x link on Video card and get 8x speed on Gen 3

    mean they can put more stuff, with less link, not faster stuff
    Reply
  • mode_13h - Tuesday, May 18, 2021 - link

    > you can put 4x link on Video card and get 8x speed on Gen 3

    In terms of power-efficiency, I'd bet the wider, slower link is better.

    > mean they can put more stuff, with less link, not faster stuff

    It's a laptop. So, prolly not gonna run out of PCIe lanes.
    Reply
  • gagegfg - Monday, May 17, 2021 - link

    "and if anticipated, great gaming performance"...
    Inside this notebook case he had a hard time controlling the temperature, if you add a 100W GPU, where is the rest for this cpu?
    mmm .... it's going to be interesting.
    Reply
  • Matthias B V - Monday, May 17, 2021 - link

    Most OEMs still prefer Intel as it has capacity that AMD can't offer and even more it has better features and integration such as AV1 coding, USB / TB 4.0, Intel WIFI etc.

    Also Intels provides better support for OEMs in design and issues.
    Reply
  • Gigaplex - Monday, May 17, 2021 - link

    AMD systems can provide TB support, there's no technical limitation preventing it. Intel WiFi chips are standalone cards, which also work fine in AMD systems (my AMD board has Intel WiFi). There's no reason to use an Intel CPU for either of those features. Reply
  • Retycint - Monday, May 17, 2021 - link

    The fact that not a single AMD laptop has thunderbolt, points to an issue with cost of implementation/PCI lanes limitations etc. which apparently doesn't exist on Intel CPUs, given how many Intel laptops come with TB as default. This is a fact, and talking about what's possible theoretically doesn't change the facts that AMD systems lack TB Reply
  • CityBlue - Monday, May 17, 2021 - link

    > The fact that not a single AMD laptop has thunderbolt, points to an issue with cost of implementation/PCI lanes limitations etc.

    Perhaps. Or it's simply a reflection of the fact that there is only niche demand for TB.

    It's on Intel based laptops because it's supported by the chipset so pretty much a no-brainer (or alternatively, Intel mandates it is included, in order to try and make it more relevant?)

    However the vast majority of laptop consumers don't need, want or care about TB, so the extra cost to include it in AMD laptops doesn't appear justified. I'm sure a vendor could include TB on an AMD laptop if they ever thought they'd get a reasonable return on the extra cost.

    And maybe now that Intel have been kicked in to touch by Apple, Intel might lose interest in TB in future.

    TB has its fans, but it also has the distinct whiff of being the next FireWire.
    Reply
  • RobJoy - Tuesday, May 18, 2021 - link

    The fact that TB still exists, baffles me.
    We all should move on.
    Reply

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