CPU_XOR_S - Linux


CPU_XOR_S is a Linux command used to perform a bitwise XOR (exclusive OR) operation on the CPU model-specific registers (MSRs). It allows precise and advanced manipulation of CPU settings, primarily used in overclocking scenarios or debugging at the lowest system level.


CPU_XOR_S opt reg val


  • opt is the operation to be performed, either "xor" (default) or "xor_clear".
  • reg is the MSR address in hexadecimal format (e.g., 0x1A0).
  • val is the bitmask value to XOR with the MSR.


| Option | Description | Default Value |
| "xor" | Perform a bitwise XOR operation on the MSR. | N/A |
| "xor_clear" | Perform a bitwise XOR operation and then clear the changed bits back to 0. | N/A |


XOR a specific bit in MSR 0x1A0 to enable overclocking:

CPU_XOR_S xor 0x1A0 0x00000001

XOR and clear bits in MSR 0x1A0 to disable power saving:

CPU_XOR_S xor_clear 0x1A0 0x0000000F

Common Issues

  • Incorrect MSR address: Ensure you use the correct MSR address for your intended operation. Check your CPU documentation or reference reliable sources to obtain the correct MSR addresses.
  • Insufficient permissions: CPU_XOR_S requires root privileges to run successfully. Ensure you are running the command as the root user or using sudo to gain necessary permissions.


CPU_XOR_S can be integrated with other commands for advanced tasks:

  • bash: Use CPU_XOR_S in scripts to automate MSR manipulations.
  • i2cset: Combine with i2cset to modify registers on connected I2C devices, such as temperature sensors.

Related Commands

  • rdmsr, wrmsr: Low-level MSR read and write utilities.
  • cpuid: Displays CPU information, including MSR addresses.