Finding MSR Address for iGPU Frequency (i5-8250U, iGPU: UHD 620)
In this article, we will discuss the process of finding the Model Specific Register (MSR) address for the integrated graphics processor (iGPU) frequency, specifically for the Intel Core i5-8250U with the UHD 620 iGPU. Although Intel's official documentation for the 8th generation core processors seems to be deleted, there are alternative ways to obtain the required information.
Understanding MSR and iGPU Frequency
Model Specific Registers (MSRs) are special registers in the x86 architecture used for various purposes, including controlling and monitoring system components. The iGPU frequency can be adjusted by accessing specific MSRs. However, finding the correct MSR address is not always straightforward.
Finding MSR Address for iGPU Frequency
To find the MSR address for iGPU frequency, we can rely on community-driven resources and open-source projects. One such project is the Linux kernel, which contains files documenting various hardware-related information.
First, clone the Linux kernel repository:
git clone
Next, navigate to the documentation directory:
cd linux/Documentation/intel-pstate
In this directory, you will find a file named pmqos-intel.txt. This file contains information about the MSR addresses for various Intel processors, including the i5-8250U.
Search for the i5-8250U in the file. You will find the following entries:
#define MSR_PLATFORM_INFO 0x000000CE
#define MSR_PKG_POWER_INFO 0x000000CF
#define MSR_PP0_POLICY 0x00001A0
#define MSR_PP0_STATUS 0x00001A1
#define MSR_PP1_POLICY 0x00001A2
#define MSR_PP1_STATUS 0x00001A3
These MSR addresses are related to power management and performance monitoring, but they are not the MSR address for iGPU frequency. To find the iGPU frequency MSR address, you need to look for the IA32_PERF_CAPABILITIES_INTEL MSR.
Search for IA32_PERF_CAPABILITIES_INTEL in the pmqos-intel.txt file:
#define MSR_PERF_CAPABILITIES_INTEL 0x345
This is the MSR address you are looking for: 0x345.
Adjusting iGPU Frequency
Once you have the MSR address, you can use various tools to adjust the iGPU frequency. For example, you can use the msr-tools package on Linux to read and write to MSRs. However, adjusting iGPU frequency is beyond the scope of this article.
Finding the MSR address for iGPU frequency can be challenging, especially when official documentation is not available. In this article, we discussed how to find the MSR address for the Intel Core i5-8250U with the UHD 620 iGPU using community-driven resources and open-source projects. The MSR address for the i5-8250U is 0x345.
References
- Linux kernel repository:
- msr-tools package: