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AMD Ryzen 7040 Series Shows Great AVX-512 Performance For Laptops / Mobile / Edge

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  • #11
    Originally posted by stormcrow View Post
    That's not a 7040.
    What? It's the exact same CPU and Laptop.

    It would be relevant to know if AVX-512 makes much of a difference between the 7040 and 12th or 13th gen Intel equivalent sans the extension.
    And that's what the older article shows at least for 12th gen.

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    • #12
      Originally posted by avis View Post
      And I've a got a Ryzen 7 7840HS based laptop, perhaps the only one in my country. I guess almost 8 years is enough for my previous laptop.

      Haven't run Linux on the new one yet because SystemRescue doesn't support its WiFi card, it has no NIC/LAN and I have no large enough USB flash drive to copy my previous laptop Linux partition to it, so it will take time to figure it all out. I'll check if Fedora Live ISO works on it and then will try to send the data via Wi-Fi.

      AMD laptops unfortunately have some obscure Wi-Fi cards which don't always work nicely with Linux. Intel laptops with Intel AX201 Wi-Fi work near perfectly.
      Yeah, Up until my latest notebook I was always just swapping out the wi-fi cards to Intel. My latest AMD notebook has a Realtek RTL8852AE in it that seems to work great with current Linux kernels. It's always a shame to have to open up a notebook computer to swap wi-fi cards but quite often it's worth it.

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      • #13
        Originally posted by ddriver View Post

        The article investigates avx 512 performance, it doesn't compare apples to oranges. But the perf per watt is core count agnostic, and intel is getting decimated there.

        Of course those are older gen chips as well, I suspect 12 and 13 gen will to a tad better.
        Of course they are, the more cores you have the more performance efficient you are, and it is quite old CPU at this point. It is almost 3 years at this point since launch for 11th gen tiger lake.

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        • #14
          Originally posted by piotrj3 View Post

          Of course they are, the more cores you have the more performance efficient you are, and it is quite old CPU at this point. It is almost 3 years at this point since launch for 11th gen tiger lake.
          12th and 13th dont support AVX-512. It should have interesting results

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          • #15
            Originally posted by stormcrow View Post
            That's not to say I'm letting Intel off for its artificial differentiation of products, only that from a practical standpoint most consumers aren't going to care.
            It's not artificial differentiation. It's simply that their E-cores don't have AVX-512. Intel decided adding it would make them too big and hurt other use cases for those cores (i.e. Sierra Forest). Going hybrid-ISA would open a can of worms and introduce plenty of performance regressions vs. simply disabling it.

            I'm sure they evaluated the hybrid-ISA option, as evidenced by the fact that they didn't fuse off the functionality in early Alder Lakes. The only reason to leave it accessible was so they could experiment with hybrid-ISA, and I think they made the right choice not to go down that rabbit hole.
            Last edited by coder; 13 July 2023, 10:52 PM.

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            • #16
              Originally posted by coder View Post
              It's not artificial differentiation. It's simply that their E-cores don't have AVX-512. Intel decided adding it would make them too big and hurt other use cases for those cores (i.e. Sierra Forest). Going hybrid-ISA would open a can of worms and introduce plenty of performance regressions vs. simply disabling it.

              I'm sure they evaluated the hybrid-ISA option, as evidenced by the fact that they didn't fuse off the functionality in early Alder Lakes. The only reason to leave it accessible was so they could experiment with hybrid-ISA, and I think they made the right choice not to go down that rabbit hole.
              That's an artificial distinction. It doesn't matter if the efficiency cores have the extension or not. This has been hashed at nauseum in many places. There's no technical reason the AVX-512 extensions couldn't be restricted to performance settings. It is, after all, a performance enhancement. The reasons given are artificial. I think it was the wrong choice because they've already done so, unofficially.

              Anux The article in the link given was talking about a 7840 (eight not zero) model AMD CPU not a 7040 as in this article, or perhaps I misread it.

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              • #17
                Originally posted by stormcrow View Post
                Anux The article in the link given was talking about a 7840 (eight not zero) model AMD CPU not a 7040 as in this article, or perhaps I misread it.
                This one is a 7840. It's somewhat confusing, but they call this series of processors "7040" which sounds more like a specific SKU. Something like "7X40" might be more clear, but they already use X a lot .

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                • #18
                  Originally posted by stormcrow View Post
                  It doesn't matter if the efficiency cores have the extension or not.
                  Sure it does. A naive program (which is most of them) spawns one thread for every hardware thread and oversubscribes the P-cores. Contention for those P-cores causes excessive context switches, cache thrashing, and more latency on thread-to-thread communication or around resources under heavy contention. Meanwhile, the E-cores (which are each more than half as fast as P-cores) twiddle their thumbs.

                  Furthermore, if you compared performance of the P-cores running AVX-512 workloads vs. all cores running AVX2 workloads, the all-core scenario would average the same or better performance. Even in this article, AVX-512 benefited Ice Lake by 34.5%, Tiger Lake by 34.1%, and Phoenix by 54.2%. On floating point workloads, E-cores have been shown to be about 54% as fast as a P-core, on Alder Lake, making their decision probably either a win or a wash. However, Raptor Lake's 2x E-core count makes it a decisive win for them. And that's only considering the impact on workloads which could benefit significantly from AVX-512, which is the minority of client workloads.

                  Moreover, the E-cores aren't just a cost-efficient way to add performance, they're also energy-efficient. The addition of more E-cores is a big reason for Raptor Lake's improved efficiency. That's especially important, when Intel is on a less-efficient process node than AMD.

                  Originally posted by stormcrow View Post
                  There's no technical reason the AVX-512 extensions couldn't be restricted to performance settings.
                  Technically plausible, but too often would result in performance regressions, as I said.

                  People only look at the plausibility aspect and don't think hard enough about the second part. There's a lot of fuzzy thinking, around this whole issue. It's mostly people who are mad because they feel like they're losing something and that feeling of aggrievement clouds their ability to think about the big picture.

                  Originally posted by stormcrow View Post
                  Anux The article in the link given was talking about a 7840 (eight not zero) model AMD CPU not a 7040 as in this article, or perhaps I misread it.
                  This is a case of confusion over AMD's nomeclature. What they mean isn't 7040, but rather 7x40. They do the same thing with EPYC model numbers, talking about 7002 to mean Rome, 7003 to mean Milan, etc. In those cases, only the first and last digits count. In this case, it's the first one and the last two. I blame AMD for creating this confusion.

                  Originally posted by pWe00Iri3e7Z9lHOX2Qx View Post
                  Something like "7X40" might be more clear, but they already use X a lot .
                  Well, lower-case x would be better, but they could use n, #, _, or even *. Okay, * might be too easily confused with multiplication, but what about:

                  7n40 ?


                  Nah, I still like 7x40 better.
                  Last edited by coder; 14 July 2023, 05:35 AM.

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                  • #19
                    The implementation of Intel hybrid architecture is not elegant, to put it politely. They should either make E cores more fat, or P cores less fat. Disabling AVX512 is a workaround. Making P cores less fat is probably better approach. AVX512 is not that important on client platforms and SMT/HT is not that important when there is a bunch of E cores to handle highly parallel loads.

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                    • #20
                      Originally posted by cbxbiker61 View Post

                      Yeah, Up until my latest notebook I was always just swapping out the wi-fi cards to Intel. My latest AMD notebook has a Realtek RTL8852AE in it that seems to work great with current Linux kernels. It's always a shame to have to open up a notebook computer to swap wi-fi cards but quite often it's worth it.
                      Don't buy laptops with Mediatek M.2 Wi-Fi/Bluetooth modules. They simply do not work. Damn.

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