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> Plus on laptops AMD has more cores

Some of the AMD chips don't support SMT, so maybe this statement doesn't tell the whole story. I recently looked at the Lenovo ideaPad Flex 5 that was offered in an AMD flavor with Ryzen™ 5 4500U or an Intel flavor with Core™ i5-1135G7. The AMD chip is 6 core / 6 thread, and the Intel chip is 4 core / 8 thread.

I'm supposed to care about the number of threads rather than the number of cores, n'est-ce pas?




From what I've read, SMT gives about 20-30% more performance. So 4 cores * 1.3 is 5.2, so 6 cores should still be faster.



There are AMD laptop chips with SMT as well, and Intel ones without. The 4600u, for example, is the version with SMT.


Certainly. I just wanted to present a real-life example that crossed my path a couple of weeks ago.


Not always. Some workloads would prefer to one thread per core. There are some micro-arch structures which are shared across SMT threads and will bottleneck you if they are critical for workload. Common examples; the TLB or the L1.


I'm certainly not equating one SMT core to two physical cores. But if you're an average laptop user (which you would be at the price point of my example) you're probably running a bunch of browser tabs, maybe Spotify, and some work stuff (Excel, Sublime Text, pick your poison) on the side that you're procrastinating while watching videos of space launches or cats or whatever. Much of the memory (re: your comment about bottlenecked computation structures) is just kind of waiting for later rather than being simultaneously mutated. While I'm writing this I'm running 319 processes with 1673 threads yet I'm loading my CPU 11% according to Activity Monitor on a fairly outdated 22nm Haswell chip. So I think for a consumer laptop you'd look at "more cores" in the context of "more price" and if there's some money to be saved, go with the SMT variant.

In my case it turned out to be a moot point because I couldn't get the AMD version anyway; it was available on Amazon from a third-party retailer but that's always sketchy and it was more expensive. But I think the "AMD laptops have more cores" argument deserves an asterisk because that's not really the whole story. (And to your point, having more cores doesn't necessarily guarantee superior execution if there are other aspects of the computation structure that bottleneck your workload.)


I have the 4500U and have yet to really push it to the limits. It's not for lack of trying!

https://www.youtube.com/watch?v=uKzJNIs8Pnw

I'm sure I could find a limit if I tried made-up tasks meant to do that, but it's plenty for all the real-world things I use it for.


I don't understand what's this supposed to prove. Writing a softsynth with lots of voices isn't particularly demanding?


That's Serum. Wavetable synthesizers are famously heavy on CPU. No one would run 113 Serums at once for anything practical, but they might have 113 things going. If it can handle 113 Serum instances with 7 unison voices each sounding at once, it can handle any music production task.




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