After APU2 BIOS update from v4.9.0.4 to v4.12.0.1, memory speed droped x2

[vespian]

I just upgraded from v4.9.0.4 to v4.12.0.1 and the dmidecode shows that memory now works at just 667 MT/s instead of 1333 MT/s. Why?

I have attached full outputs of dmidecode, before and after the upgarde.

Thanks in advance for any information !

dmidecode.post-update.txt
dmidecode.pre-update.txt

[miczyg1]

The DMI tables are constructed based on the information from AMD AGESA. It may be incorrectly constructed by AGESA itself. But it doesn't necessarily mean that the memory speed is halfed. Do you experience performance drop?

[pfsenseuser]

Hello,

I made a test on a Apu2C0 Board once with bios v4.12.0.1 (dmidecode: Speed: 667 MT/s) and once with bios v4.0.30 (dmidecode: Speed: 1333 MT/s) and I cannot see any performance decrease. I used memtest86 for the test.
Bios v4.0.30

Bios v4.12.0.1

[miczyg1]

Please have a look at section 7.18.4 of SMBIOS specification: https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.1.1.pdf

It looks like I did a mistake in v4.12.0.1 when creating the memory tables using AGESA provided. In v4.9.0.4 I have put the total speed of the memory (as per newer specification than 3.0.0) which is the memory clock speed (666MHz) multiplied by 2 (as per DDR - double data rate). Multiplied by 2, because DDR memory issues two transitions per clock cycle.

To sum up, value of 666MT/s reported by AGESA complies to SMBIOS specification 3.0.0 and older. I will prepare a fix for that so the speed will be correctly reported as 1333MT/s.

[miczyg1]

The issue has been fixed in v4.12.0.3