Review: AMD Ryzen 9 3950X processor - 16 cores and 32 threads for the masses

Discussion in 'Frontpage news' started by Hilbert Hagedoorn, Nov 14, 2019.

  1. Kaotik

    Kaotik Member Guru

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    Yes, it is. You design the architecture first, obviously, and the physical cores around it and you already have the main components for the CPU, it just needs the PCIe and other buses around it. But before you have that physical layout for the cores, you can't really even start working on the APU and how everything will integrate to it, it's a world of a difference despite Infinity Fabric compared to what the CPU variants need in it. It's actually pretty astonishing that they can build the APU around those cores with only ~6 months delay
    (yes, the desktop variants come about another 6 months later, but that's probably more of a business decision than anything, since you really want to push everything you can to laptops as soon as you can, so it's given the priority on physical design (while the chip itself is the same, the PCB it sits on isn't - it's actually really impressive that they managed to fit 2 chiplets + I/O-chip on the same package and be compatible with the AM4 socket (and it did require more layers to the PCB to make it possible), they tried that with 3rd gen Threadripper too but the choices they made when they cut SP3 to SP3r2 for Threadrippers simply wouldn't work with all the CPUs planned for 3rd gen anymore which is why we have sTRX4 now (with same number of pins etc))

    (also, it's 4.45 AM here and I'm drunk so sorry if the post seems to jump from thing to thing randomly)
     
  2. KingGladiator

    KingGladiator Member

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    We have a 3800x and 9700k system, so I can chime in here. The best I can do with these two systems:

    9700k - 3466/c14 - 44ns

    3800x - 3733/c16 - 68ns

    Funnily enough the 3800x can clock higher MHZ with my dual rank sticks @1t - 9700k needs to go to 2t past 3600mhz, so AMD have done a very good job with the memory controller

    Side note re gaming - I notice a far bigger gap in FPS vs all the review sites with a big OC on the 9700k . Running at 5.2ghz -1 avx vs 3800x @ 4.35ghz all core OC , the 9700k seems to be 10-30% better performing depending on title
     
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  3. Gripen90

    Gripen90 Master Guru

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    Those Time Spy CPU scores for the Ryzen 9 3900X and 3950X seem odd to me.
    I have a Ryzen 9 3900X on a Gigabyte X570 I Aorus Pro WiFi and 32GB G.Skill Trident Z Neo 3600MHz CL18, and everything is running stock, and I get a CPU score of 13080.
     
  4. Angushades

    Angushades Master Guru

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    Subjectively I went from a MSI Z390 pro carbon with a 9900k to a 3900x and x570 and i didn't notice any difference but maybe because I have been playing on 1440p @165 gsync for a long time. The reason I went AMD this time is because i could see the wind changing lol, I've been with intel since i sold my 939 and brought a C2D E6300 @1.8 to 3.2 Custom loop. I've seen this before lol P4 Netburst , skylake is at the end of the road with an architecture. Intel need to reinvent the wheel again
     
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  5. Ryu5uzaku

    Ryu5uzaku Ancient Guru

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    Considering the clock difference is nearly 20% AMD isn't doing that badly. I don't really believe that 24ns difference in latency is the biggest culprit anyway. It's a combination of things.
     
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  6. DeskStar

    DeskStar Maha Guru

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    Yes I am very glad to see AMD hitting it out of the park with the hardware and it's capabilities this go'round.

    See about clock for clock on them CPU's and I bet the Gap is either nil, or AMD takes the lead.
    Check it out and see about the difference between the two of them.
    Difference in performance is in the clock speed Gap. Hilbert has already proven IPC performance favors that of AMD being that it is a newer piece of silicon.
     
  7. iniside

    iniside New Member

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    Different memory access patterns.
    Unoptimized games tend to have lots of cache misses, that means CPU is waiting for data from RAM. Depending on how low latency there is and how good CPU prefetcher is it may or may not pull the right data from memory and in next few cycles you might not need to call main memory.

    That's theory in practice CPU prefetcher is only capable of getting data linearly from memory. Truth is there is not that many games with optimized memory layout to exploit CPU cache. Some parts of game are some not.

    There is nothing that CPU manufacturer can do about it. It is simply physical limitation of memory access speed.

    (Unless you put huggeeeee L4 cache on CPU, and I mean >4GB).

    The good part is next generation of games are going to better exploit cache locality. Both most used engines are slowly migrating towards data oriented design. In case of Unity it is full sail ahead with DOTS for everything and in case of Unreal it is rewriting core systems independently without central framework.

    DX12 and Vulkan make it pretty much mandatory to fully exploit ability to feed data from multiple threads without running in race conditions or lock hell.
     
    Last edited: Nov 18, 2019
  8. KingGladiator

    KingGladiator Member

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    Fair enough and having Gsync would really help with any min fps discrepancies between your old 9900k vs 3900x. We have a 144hz non gsync monitor and notice quite a lot of drops below 144fps on the 3800x system but not so much 9700k - but it really depends on title. Newer stuff seems to be quite good- new modern warfare for example is locked @ 144fps on both the Ryzen & Intel chips. Borderlands 3 was dropping a lot on our Ryzen but not 9700k until switching to DX12 mode and now it seems pretty close also. Probably the worst game for AMD that we play is Destiny 2 which regularly drops into the 90 fps range on the 3800k but not the case with the 9700k.

    Another Ryzen release with more IPC and even 200mhz clock speed may see parity vs current Intel chips in gaming, which would be quite the feat

    As for the 3950x - I would be keen to see someone test it with the worse chiplet disabled and then throwing more volts/maximum all core OC - possibly even with SMT off. I got my 3800x up to 4.5ghz SMT off with a good whack of voltage - would be keen to see what the better binned 3950x can do. Maybe 4.7 on 8 cores
     
  9. Loophole35

    Loophole35 Ancient Guru

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    Steve @GN got 4.9 with SMT on at just under 1.4V at -50°C with his review sample 3950x.
     
  10. KingGladiator

    KingGladiator Member

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    Thanks for that info-just looked it up and can see some tables with results

    I noticed in my own testing that with SMT off, my 3800x uses almost 50% less current under load.

    For gaming with the 3950x, might be able to turn smt off and get a pretty high frequency with a good AIO/air cooler without the chip melting, somewhere in the 1.35-1.375v range could be doable with 16 cores or even better with 8 . would love to play around with one of those :D
     
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  11. The Goose

    The Goose Ancient Guru

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    A hand full of extra fps between the 3950x and the 3800x but almost double the price, think i might wait a bit longer(Jan/Feb) and see if the 3800x drop in price before retiring my i7 7700k/Asus z270 prime A and 32 gig Corsair rgb 3200
     
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  12. moab600

    moab600 Ancient Guru

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    Mine 3700X is more than enough, i'll wait till Ryzen 4000 to see what they offer, as the 3950X is already hard to find.
     

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