In the lab: Intel’s Core i7-7820X CPU

Intel's range-topping Core i9-7900X may be making the most noise on the X299 platform right now, but we imagine more builders are interested in the eight-core, 16-thread Core i7-7820X and its somewhat wallet-friendlier $599 price tag. Intel sent us an i7-7820X of our own today, and here it is:

I look forward to getting this chip in our X299 test bed as we complete our evaluation of the Core i9-7900X and its gaming chops. We'll be pitting the i7-7820X against the Ryzen 7 1800X and friends for both productivity and gaming performance soon, as well. Stay tuned.

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    • ronch
    • 2 years ago

    With quad channel support on a much more expensive platform I’m not sure pitting the 7820X against the 1800X is fair, but with the same number of cores and threads it’ll be interesting how these two chips compare.

    Edit – the real opponent for the 7820X is the 1900X.

    • ermo
    • 2 years ago

    From the included link to the product specs:

    [quote<]ECC Memory Supported ‡ No[/quote<] In the footnotes, it says that ECC support depends on the motherboard. Does that imply that the IMC supports ECC but that it's up to the vendor to enable it? In addition (and assuming that the industry is distancing itself from SLI/CF), the 28-16 = 12 PCIe lanes for storage etc. sounds decent enough if you need a decently priced workstation with good AVX-512 performance and ECC.

    • psuedonymous
    • 2 years ago

    Threadripper ITX does not exist so I can dismiss that out of hand. The i7-7820X is definitely looking like the sweet-spot in price/perf for x299. The i7-7800X lacks TB3, and the i9-7900X is a near doubling in price for two more cores (and a reduced base clock).

    • ALiLPinkMonster
    • 2 years ago

    So many tantalizing reviews in the works. My body is ready, TR. Hit me with those sweet, sweet benchmarks of things I can’t afford.

    • blahsaysblah
    • 2 years ago

    If you take a close look, doesnt that seem like a lot of sealant? Wonder if deliding will bring IHS closer to CPU and give better temps like all other recent Intel CPUs.

    They even printed box so you can make sure to put IHS back in right place without special tools.

      • Chrispy_
      • 2 years ago

      All that sealant is to keep the nasty white goo in there, because Intel are too cheapskate to use solder.

        • blahsaysblah
        • 2 years ago

        The TIM inside is good, vs TIM on stock cooler being not as good. Reviews i read was that when you delid, all the improvement(except for going liquid metal) is from lowering IHS closer to CPU.

        I could see it in my delids, my own has the thinnest layer of sealant to remove when i relid, versus original was noticeably thicker and a lot more material to remove.

      • psuedonymous
      • 2 years ago

      X299 has an internal PCB the die sits on on top of the base PCB that is exposed to the underside. The die sits up ‘higher’ then you would expect if you’re used to LGA115x chips.

    • Kougar
    • 2 years ago

    Nice. Hope you have a cooler or block that fully fits over that ~473 mm2 die.

      • CuttinHobo
      • 2 years ago

      Think a Chevy aluminum block would be big enough?

        • Kougar
        • 2 years ago

        Probably too big. Could still use the heater core though. 😉

        I mention blocks because those will be the most affected by the size, the entire die will need cooling fins for decent cooling performance. Swiftech is planning Threadripper and HCC die specific blocks but I don’t think they’re near to releasing them yet.

    • Fonbu
    • 2 years ago

    Note the “Intel Confidential” on the top. So this is a version of an engineering sample? So not an actual retail sample.

      • Jeff Kampman
      • 2 years ago

      This chip will correctly identify itself as an i7-7820X to CPU-Z and other applications. The “Intel Confidential” mark is to prevent resale by the unscrupulous.

        • sreams
        • 2 years ago

        So the scrupulous are allowed to sell these?

          • blahsaysblah
          • 2 years ago

          How many scruples?

        • CuttinHobo
        • 2 years ago

        OR… It’s a special review sample that turbos itself to 6GHz to sweep all the benches! I’m sure I can rearrange “Intel Confidential” to find something incriminating…

        Foil hats for all!

        • ronch
        • 2 years ago

        Offered at the right price in the black market I gather not everyone will pass up this deal. Say, someone sold you what is effectively a $600 chip for $300 or so.

    • Pancake
    • 2 years ago

    So for fifty bucks less you can get the Threadripper 1900x. Hmm. Intel guaranteed peace of mind, stability and reliability or… that other stuff. Decisions. Decisions.

    What a time to be alive!

      • sleeprae
      • 2 years ago

      Yeah, I’m hard-pressed to see the real use case for this chip for a new build.

      Disclaimer: Own both a 1700X and a 7900X, but tend towards Intel.

        • Srsly_Bro
        • 2 years ago

        You also now own two -1s.

        sup?

          • DrDominodog51
          • 2 years ago

          Saaaaaaaaawwwwww duuuudddddeeee

          • sleeprae
          • 2 years ago

          I just like to point out that I buy and use both depending on what best suits the need at the time. I tend towards Intel, but am no fanboy. Guess that offends some people.

            • swaaye
            • 2 years ago

            Welcome to the public discussion board lifestyle! Made even better by the advent of the thumbs buttons and their easy anonymity combined with brainless simplicity!

        • blargh4
        • 2 years ago

        I’m probably going to use it for my next build because I want the fastest single-thread performance and still some headroom for occasional workloads that scale well to more than 4 cores. For my money, this chip seems like a sweet spot.

      • Krogoth
      • 2 years ago

      None of the is really true anymore.

      Intel platforms have their set of stupid issues and AMD isn’t in the K6 into the early K7 era either.

        • cynan
        • 2 years ago

        But my dear Krogoth, surely it’s the very ambiguity of a straightforward 8-core HEDT supreme champion that makes the 1900x/7820x choice so dog on [b<]impressive[/b<]? Coming from a 3960k, the pitting of these two CPUs may finally get me interested in seriously considering a platform upgrade. At the very least, Jeff will have something to sink his teeth into when the x1900 arrives in his lab.

        • srg86
        • 2 years ago

        I totally disagree, Intel arn’t perfect by any means, but even past the K7 era they are more bullet proof. I’m not going back.

        The very mention of using Asmedia designs in the chipset put me off.

      • cynan
      • 2 years ago

      That’s exactly what I thought when Jeff mentioned an upcoming comparison with the 1800x. The real contender we’re all chomping at the bit to see a cage match main event with is his memory-bandwidth- PCIe-enhanced mutant bigger brother for $50 less.

      • Vaughn
      • 2 years ago

      i’m more curious to see i7-7820X vs TR 1900X

      • jts888
      • 2 years ago

      TR: $50 less, 36 more PCIe lanes, ECC support, and allegedly also RDIMM/LRDIMM support.
      i9: massive AVX512 throughput, twice the L2 per core, “flatter” multiprocessing topology, and maybe lower (nominal) TDP.

      I’m most interested in the TR 1920 non-X at the moment and will get one if/when it hits $650, since I basically have no use for AVX and would like a 128 GB ECC setup for use largely with int-heavy VMs.

      • Klimax
      • 2 years ago

      50 dollars for full AVX, IPC and not having to battle cross-CCX fun.

      What decisions are you talking about?

        • Kougar
        • 2 years ago

        “Full AVX” being AVX512 which nothing actually uses yet. Threadripper will perform better in large AVX 128/256 workloads.

          • RAGEPRO
          • 2 years ago

          He’s probably referring to the fact that Ryzen actually only has half-width AVX(2). All else being equal (clocks, etc) Ryzen can only ever be half as fast as an Intel big core (Haswell and later) on AVX workloads.

          Nothing to do with AVX512.

            • Anonymous Coward
            • 2 years ago

            Its impressive that AMD can challenge Intel at all in the workstation space, despite that major gap in floating point hardware. Using a monolithic die has left the door open for AMD to crash the party with a decidedly less-optimal architecture offered in larger quantities.

        • the
        • 2 years ago

        The i7-7820 doesn’t support full AVX-512 as 512 bit operations are split into 256 bit chunks for execution.

        [url=https://techreport.com/review/32111/intel-core-i9-7900x-cpu-reviewed-part-one<]From the i9 7900 review:[/url<][quote<] What's more, not every Core X chip in the lineup will enjoy the same boost in SIMD performance from AVX-512. Only the Core i9 series of CPUs will ship with the dedicated AVX-512 FMA. The Core i7-7800X and Core i7-7820X will still have the wider registers for AVX-512, but they'll only execute instructions using the pair of 256-bit AVX units common to all Skylake chips. [/quote<]

          • chuckula
          • 2 years ago

          The rumors of the 7820X not having “real” AVX-512 (whatever that means) appear to be unfounded:

          [url<]http://www.numberworld.org/y-cruncher/[/url<] [url<]http://www.pcgameshardware.de/Skylake-X-Codename-266252/News/Core-i7-7800X-AVX512-Durchsatz-1232713/[/url<]

            • jts888
            • 2 years ago

            FWIW, I talked to Alex (aka “Mystical”, the guy who found the Ryzen FMA bug) a month or so ago, and his take on Skylake-X and Skylake-E then was that memory bandwidth was actually limiting AVX512 throughput more than anything else, including the special clock throttling.

            Apparently the 128B datapath into the cores only extends to the 32KiB L1D and not even to L2, so it’s very easy for non-trivial applications to bottleneck there..

            “Real” AVX512 is more a Platonic ideal than something obtainable on a Xeon in reality today it seems.

          • Jeff Kampman
          • 2 years ago

          This is a question of throughput rather than support.

          Core i9 CPUs can execute two AVX-512 operations in parallel by using both the dedicated AVX-512 unit and the two 256-bit-wide AVX2 units in each Skylake-X core.

          Skylake-X Core i7 CPUs still offer full support for the AVX-512 subsets that the microarchitecture can execute. They just have half the potential throughput, core-for-core, of the Core i9 chips because they don’t have the dedicated AVX-512 FMA enabled. Instead, they rely on the pair of 256-bit-wide execution units to perform one AVX-512 operation.

          This is like saying Ryzen CPUs don’t support AVX2 because they can only execute one AVX2 operation at a time versus the two that Haswell and newer Intel chips have been able to perform. Ryzen takes a similar “split this 256-bit operation into two 128-bit operations” approach with AVX2 like that of Skylake-X Core i7s and AVX-512 instructions.

            • the
            • 2 years ago

            You are correct that throughput is indeed a better word than support there.

            Main point though is that Intel is handicapping AVX-512 performance there in a similar fashion to how AMD has implemented AVX/AVX2 on Ryzen.

        • hansmuff
        • 2 years ago

        [url=https://en.wikipedia.org/wiki/AVX-512#CPUs_with_AVX-512<]You never go Full AVX-512.[/url<] Short of a few professional applications, AVX-512 won't matter for anything for a good long while. Not that it's bad to have, by any means, but it's kinda like TSX today: took Intel a metric fuck ton of work to get working over multiple CPU generations and will not show you benefits in consumer workloads at this time and only $diety knows when. Again, not BAD but not a very good purchase criterion at this time.

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