Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
Vol. 3 B-39
MODEL-SPECIFIC REGISTERS (MSRS)
63H 99 MSR_
LASTBRANCH_3_
TO_LIP
Unique Last Branch Record 3 To IP. (R/W)
See description of
MSR_LASTBRANCH_0_TO_LIP.
79H 121 IA32_BIOS_
UPDT_TRIG
Unique BIOS Update Trigger Register. (R/W)
see Table B-2
8BH 139 IA32_BIOS_
SIGN_ID
Unique BIOS Update Signature ID. (RO)
see Table B-2
C1H 193 IA32_PMC0 Unique Performance counter register. see Table B-2
C2H 194 IA32_PMC1 Unique Performance counter register. see Table B-2
CDH 205 MSR_FSB_FREQ Shared Scaleable Bus Speed(RO).
This field indicates the intended scaleable bus
clock speed for processors based on Intel Core
microarchitecture:
2:0 101B: 100 MHz (FSB 400)
001B: 133 MHz (FSB 533)
011B: 167 MHz (FSB 667)
010B: 200 MHz (FSB 800)
000B: 267 MHz (FSB 1067)
100B: 333 MHz (FSB 1333)
133.33 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 001B.
166.67 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 011B.
266.67 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 000B.
333.33 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 100B.
63:3 Reserved
CDH 205 MSR_FSB_FREQ Shared Scaleable Bus Speed(RO).
This field indicates the intended scaleable bus
clock speed for processors based on Enhanced
Intel Core microarchitecture:
Table B-3. MSRs in Processors Based on Intel Core Microarchitecture (Contd.)
Register
Address Register Name
Shared/
Unique Bit Description
Hex Dec