http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf >MSRC001_102A[7:6] - ThrottleNbInterface.
>Read-write. This field specifies the number of clocks the core must wait
>between sending each packet of information to the NB. This field must be programmed to a value
>greater than or equal to the number of enabled cores minus 1. See section 2.9.2 [CPU Cores and
>Downcoring]. BIOS should program this field to one less than the number of enabled cores in the
>node as follows:
>Enabled Cores Bits Definition
>1 00b 0 Clocks
>2 01b 1 Clock
>3 10b 2 Clocks
>4 11b 3 Clocks
M2A-VM HDMI(BIOS 2302) + 720BEで全コア常に11b(3Clocks)。Downcoreしても同じ。
MSRの読み方↓
CrystalCPUID - Function->MSR Walker->Start,Endに0xc001102aを入力->START。
OlsMsrEditor - MSR indexに0xc001102aを入力->CPUコア選択->RDMSRをクリック。
Linuxではmodprobe msrして/dev/cpu/0/msrをopenしてpread( ... , 0xc001102a)。