Is it normal for Zen 2 all-core to max out at 4 GHz? My 3900X in games seems to top out there

Discussion in 'Processors and motherboards AMD' started by BlindBison, Apr 19, 2021.

  1. BlindBison

    BlindBison Master Guru

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    Hi there all,

    Recently I updated my BIOS to latest (ASRock Phantom Gaming 4) as well as installed the latest Chipset Drivers from AMD (X570).

    In the BIOS the only things I've changed are to switch on XMP for the RAM and then to switch PBO from "Auto" (default) to "Enabled".

    I was recently testing out some multithreaded games like Crysis 3 and noticed that the CPU frequency only reached to about 4 GHz rather than say, 4.2 like I expected.

    Is this normal or something I should be concerned about? Thanks!

    EDIT: https://www.reddit.com/r/Amd/comments/ckpvhc/3900x_all_core_41_ghz/

    Seems like here^^^ they've encountered similar ish performance/frequency -- I don't quite reach 4.1 ghz, but it looks like when I use HWiNFO that it's at maybe between 4 and 4.1 ghz when the CPU is under load in multithreaded games.
     
    Last edited: Apr 19, 2021
  2. AsiJu

    AsiJu Ancient Guru

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    While you should reach higher clocks there's always some luck involved.

    My 3800X does all core between 4.3 ... 4.4 when gaming.
    Under heavy load like Cinebench all core is 4.2.

    But based on your other thread set PBO to Enabled and see what happens.
     
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  3. Digilator

    Digilator Master Guru

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    What are your temperatures? What cooler are you using?
     
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  4. RealNC

    RealNC Ancient Guru

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    PBO is useless, btw. You might as well disable it.
     

  5. Undying

    Undying Ancient Guru

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    Without pbo you loose single core boost.
     
  6. Truder

    Truder Maha Guru

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    PBO is not the same as PB and PB2 (Precision Boost and Precision Boost 2 respectively). PB and PB2 is what's responsible for single core boosting and these are enabled by default.

    PBO (Precision Boost Overdrive) handles PPT (Package Power Tracking - total power going through the CPU), EDC (Electrical Design Current - total amps going through the CPU) and TDC (Thermal Design Current - total current going through the CPU depending on temperature).

    All PBO does is lift these 3 values to potentially allow for better multi-core performance - this does not necessarily mean clocks will be higher but can mean that more work can be done or improve stability. Imagine it like this - You have a road and on this road cars can only do 70mph(the speed the car can do is the clock speed) however as more cars use the road, congestion builds up so all the cars have to slow down to 60mph to be able to travel on this road. When you turn PBO on you enable more cars to go down the road, lets say, PBO widens the road. The cars can still only do 70mph, it hasn't made the cars faster but it's allowed more cars use the road.

    Not really sure if this helps but honestly, since Zen2, overclocking Ryzen is a pain in the arse, especially on lowerend SKUs as Ryzen chips are binned quite aggressively (if you use software such as CTR it can reveal the binning quality of the CPUs, if we take the 3700X as an example, very few achieve a rating over "Silver" with the CTR software, most only achieve Bronze) but typically speaking, there's no need to overclock as the chips boost to their best whenever they can, achieving better performance comes in the way of optimising ram and possibly undervolting (however undervolting has its own issues and you may end up encountering clock stretching, this is where the clock speed is high but the performance is low). Zen3 benefits a lot with undervolting, especially with the curve optimiser that can be utilised on Zen3.
     
    Last edited: Apr 19, 2021
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  7. cucaulay malkin

    cucaulay malkin Ancient Guru

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    single core boost is useless

    list all software that you currently have installed that uses single core boost.
     
  8. Undying

    Undying Ancient Guru

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    Why? If you overclock ryzen manually you are locking your single core boost to your slowest core. If you let the "pbo" do its thing it boosts higher on the single core.
     
  9. cucaulay malkin

    cucaulay malkin Ancient Guru

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    yeah but what software uses single core boost ?
    did you actually ever observe clocks during the things your're using your pc for ?

    in my experience,the cpu will usually chill and use base clocks rather than ramp up voltage and frequency to maximize single core performance for apps that don't benefit from it much.all core is important,single - not really.
     
  10. RealNC

    RealNC Ancient Guru

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    Single core boost works fine here without PBO.

    Edit: If "single core boost" refers to the CPU still going above base clock for individual cores, that is. Do you mean this:

    witcher3_2021_04_19_15_16_07_876.jpg

    This is with PBO disabled.
     
    Last edited: Apr 19, 2021

  11. GarrettL

    GarrettL Master Guru

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    The Zen cpu's perform best with very good cooling for maximum clocks.

    OP, what cooler are you using for your 3900x? What are your pc specs?
     
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  12. mbk1969

    mbk1969 Ancient Guru

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  13. BlindBison

    BlindBison Master Guru

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    This is with PBO set in the BIOS to Enabled rather than auto which is the default. I do not have Auto OC or Ryzen Master involved for this test however. Thanks,
     
  14. BlindBison

    BlindBison Master Guru

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    I’m using a liquid cooler and my temps are great fortunately (I almost never push 85 even when gaming).
     
  15. BlindBison

    BlindBison Master Guru

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    My temps are good (liquid cooled) and even while gaming it usually sits between 75-80 C, maybe 85 so I’m not concerned with the temps really.

    I have a Phantom Gaming 4 ASRock board (X570) with 3900X + 2080 Super and 2 x 16 Gig RAM Sticks clocked to 2933 MHz (14/17/17/17/36 timings). My ram is “supposed” to be 3200 MHz capable, but I could never get the machine to boot at anything above 2933 :(

    Right now I’m using stock board settings other than the RAM speeds/timings and I’ve switched PBO from auto (default) to Enabled.

    I could try switching PBO from enabled to Advanced then setting a MHz offset of 100 and changing the limits from auto to motherboard there.
     

  16. jbscotchman

    jbscotchman Ancient Guru

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    Those temps seem kinda high especially with liquid cooling. Also your ram not reaching 3200mhz could be an issue.
     
  17. AsiJu

    AsiJu Ancient Guru

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    Yeah you should definitely have lower temps esp. with liquid.

    For ref. my 3800X hovers around 60 ... 65 C while gaming on air.

    Repaste your CPU and make sure your liquid cooler is ok.
    IIRC Ryzen's start limiting max boost already past 60 C, in 25 .. 50 MHz steps.
     
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  18. BlindBison

    BlindBison Master Guru

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    Oh really, thanks that's good to know -- I'll try repasting this afternoon and report back. I did notice that with Cinebench / All stock bios settings other than PBO -> Enabled and the RAM speed/timings, I get single core 4.2 GHz in cinebench, but only 3.8 GHz on all-core in cinebench.

    Meanwhile in Crysis 3 with PBO set to Advanced + limits set to motherboard rather than auto + MHz offset of 200 (I don't think it runs this flat, but rather it seems to factor it into how high the auto boost "can" go) I was getting around 4-4.1 GHz most of the time (though I did occasionally see 4.2 rarely).
     
  19. BlindBison

    BlindBison Master Guru

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    Yeah, I was pretty miffed when I found out my 3200 MHz RAM wouldn't boot correctly at the XMP settings -- I made another thread for this back in the day, but never found a way to resolve it so I've been running it at the best completely stable/error free values I could which is:

    2 x 16 GB RAM sticks clocked at 2933 MHz w/ 14/17/17/17/36 primary timings. What can you do eh? The claimed XMP values are supposed to be 3200 MHz w/ 16/18/18/18/38 timings. There have been BIOS updates since then so maybe at somepoint I'll try again with my testing. I used memtest64 and the ryzen dram calc's memtests to ensure stability in the values. Interestingly memtest64 would find errors eventually that ryzen dram calc's tests never did.
     
  20. jbscotchman

    jbscotchman Ancient Guru

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    You may want to consider RMA'ing that ram if you still can. There's no reason it shouldn't be getting 3200mhz paired with a 3900x.
     
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