Requesting cpuid function ID 0x80000006 on a Ryzen 7 3700X returns 0x01009140.
So the value for the L3 cache associativity (bits 12-15) is 0x9
According to the spec(PDF page 75) this value is reserved.
Any idea were the issue lies here?
Is the spec wrong or the CPU bugged?
Edit: We now have a Ryzen 5 3600 which shows also returns 0x9 bits 12-15.
No, that L2/L3 cache associativity value (0x9) means "Please look at CPUID.8000_001D"
Thank you for the clarification.
Where in the docs is that noted?
I can't find it in
https://www.amd.com/system/files/TechDocs/54945_3.03_ppr_ZP_B2_pub.zip
Is that the wrong doc?
Am 22.10.19 um 22:12 schrieb avk:
Community <https://community.amd.com/?et=watches.email.thread>
>
Re: Ryzen 7 3700X: cpuid function ID 0x80000006 returns wrong
number for L3 cache associativity
in /Processors/
The ZP-B2 document is about Zen 1+, not Zen 2 . Please read this: https://www.amd.com/system/files/TechDocs/56176_ppr_Family_17h_Model_71h_B0_pub_Rev_3.06.zip, page 74. BTW, the best way to check AMD Tech Doc updates is to visit here: https://www.amd.com/en/support/tech-docs
Also, AMD still didn't explain at least 6 (six!) CPUID flags of their CPUs. Do you wish to know which ones?
Perfect.
I looked here:
https://developer.amd.com/resources/developer-guides-manuals/ and
couldn't find anything newer than my linked document.
Also, AMD still didn't explain at least 6 (six!) CPUID flags of their
CPUs. Do you wish to know which ones?
Sure, why not?
Here they are:
8000_0007.EBX[04] - appeared along with Zen 2;
8000_0008.EBX[10, 13, 19, 23] - appeared along with Zen 2.
8000_000A.EDX[11] - appeared along with Piledriver;
8000_001F.EAX[16] - appeared along with Zen 2.
See it for yourself in my tiny utility avkSI, at the "Flag2" & "Flag3" tabs.
BTW, Intel also has an unexplained (publically) CPUID bit, 0000_0007[0].EDX[13]. I think it somehow is connected with those Spectre/Meltdown/etc. patches. I've noticed that bit in Skylake (i5-6300HQ) + Win10 v1903, along with 0000_0007[0].EDX[10] = MD-Clear.
No, that L2/L3 cache associativity value (0x9) means "Please look at CPUID.8000_001D"