PC Processors

[ltron]

I have a strange issue with my 3900X, on average the cores in the slow CCD 1 chiplet (4300-4400MHz) are ranked as faster in the CPU's firmware than the cores in the fast CCD 0 chiplet (4500-4650MHz). When applications are not using my fastest core 0 (correctly ranked) they will use a core pair that are ranked #2 and #3 fastest (incorrectly), these are cores 6 and 8 from the slow CCD 1 chiplet and they are only capable of 4.425GHz max which results in low Cinebench R15 and R20 single core scores of 205 and 510 respectively, multi core is fine at 3200 and 7250. Other people get 520-535 from what I've seen.

Here is a HWInfo screenshot and a Ryzen Master screenshot (attached) so you can see what I mean, in HWInfo the #numbers on the right are how the cores have been ranked in the factory and written into the firmware and the #numbers on the left are what Windows thinks the ranking is. Can you check this on your CPU, particularly those with low Cinebench scores?

I have confirmed this ranking in Linux too so it's not a Windows issue and all screenshots I've seen from other people have shown CCD 0 correctly ranked above CCD 1. I have confirmed that all cores in CCD 0 do at least 4500 MHz by disabling CCD 1 (which resulted in 521 in Cinebench R20 and 210 in R15) whereas all cores in CCD 1 do at most 4425 MHz. I think someone may have made a mistake in the factory and ranked the cores wrong. Is there a plausible explanation for this ranking being correct and does anyone else have this problem? I'm asking for educational purposes, not that I can fix it as that's up to AMD (hopefully they can fix it if I can determine the problem is not unique to me) and I certainly wouldn't RMA a CPU over this.

This CPU core ranking is replicated across both an MSI X570 ACE and a Gigabyte X570 Master and multiple BIOS versions and AGESAs. CPU-z is fine at 541 single core (it does its own thing and uses core 0 which is my fastest core so that's why it's not affected by the ranking) and Geekbench 5 is fine probably for the same reason and I get 1315 single core. I ran Aida 64 Memory Latency test which loads core 0 and gives me 4.6GHz+ so I could show the CPU is capable of these speeds in the screenshot.

My specs:
AMD R9 3900X
Gigabyte X570 Master
32GB Crucial Ballistix CAS 16 DDR 4 3600MHz
Noctua NH-D15S
Palit GTX 1080 Gamerock Premium
Corsair RMi 1000W PSU
Corsair MP510 960GB
Windows 10 1909 64bit Pro

[hardcoregames_]

I suspect that the relative performance of the chiplet and not the clock speed is more likely the way the core logic is managed.

I suggest you simply use the machine for gaming, the GTX 1080 is suggestive and enjoy. Not many games will load the R9 3900X appreciably.

[ltron]

Hi, thanks for the reply.  Could you clarify what you mean by 'the relative performance of the chiplet' please?  I will stop worrying about it, thank you.  I was just curious whether I was the only one to have this strange core ranking.

[hardcoregames_]

Windows changed the scheduling muddying the situation considerably. Windows 1909 now looks at each thread and estimates its overall ability. This is done faster than it used to be as modern processors have lots of cores.

The redesign was in reaction to modern processors with 4 cores or more. The goal was to minimize power consumption as well as boost performance.

[misterj]

ltron, I do not know what you are complaining about.  I do not understand what you mean by chiplet (4500-4650MHz) and chiplet (4300-4400MHz).  Where did you get these numbers?  Please do not run and uninstall HWinfo - it is a bad utility and probably part of the problem, whatever the problem may be.  Please run only CB R20.  It is hard enough to keep up without your changing tests for no reason.  Your Ryzen Master (RM) screenshot has no load so shows little.  Four cores are running, the fastest running at 815 MHz.  I do not know that the cores are ranked in the factory.  How do know that?  Please post a link to a document/site.  Please run a Single core CD R20 after uninstalling all junk applications, including HWinfo, and doing a Clear CMOS.   Post a screenshot of RM during the run - simply drag-n-drop the image into your Reply.  Only one core should be at a high frequency - all others should be in Sleep or a few hundred MHz.  Close all other applications including browsers.  Please also post a screenshot of CPU-Z MB tab showing BIOS/AGESA versions.  Thanks and enjoy, John.

EDIT: I did a little research and found that this is very complex and changing subject.  The selection of the Star placement is done early at the factory at binning as ltron said.  I found this article and it references several more which I did not check.

[ltron]

Hi misterj, thank the reply.  The cores are ranked in the factory according to this: Fastest Cores: Is Windows Right? Or Ryzen Master? It's Both! The Inside Scoop & What Happens Next : ... 

The 3900X is made up of two chiplets, I know one is fast and the other is slow from my testing and this is corroborated by others.  Disabling the slow chiplet in the BIOS (CCD 1) results in higher boost clocks in Cinebench (4.5GHz+) and higher scores.  The problem is that sustained single core loads are being delegated to a core pair where the maximum frequency is only 4.425GHz resulting in lower scores compared to other people.  Their screenshots show the first 6 cores being ranked higher than the others and so they get higher boost clocks in Cinebench,  mine is the other way round but I can't find anyone else with this issue.  I'll post the image during Cinebench if you want, but I'm going to stop worrying about it, I just wanted to check if others have this issue or can provide a plausible explanation as to why my cores are ranked in this unusual way.

[josh_]

Hello,

i don't know where to ask this Question, so i'm sorry to post this here. I have very low cinebench results with my 3900x. It's only reaching around 5200-5300 Points (all cores).

My System:

Mainboard: Asus ROG Strix III

RAM: 32Gb G.Skill Tridentz 3600

SSD: Samsung EVO Plus M.2

PWS: beQuiet 800W

OS: Windows 10

I have set the PBO to Auto. RAM frequency is on 3200 Mhz. Windows Settings is on max. perfomance. I'm really shocked About this low results as most poeple reporting a score over 7000 with all cores…..