Set CPU Frequency using BIOS

In this article, we have explained how to set CPU Frequency of a server / system using BIOS settings.

You should set CPU Frequency to a custom value because different applications run at different efficiency for different frequencies. So, changing frequency is an optimization technique for server applications.

There are different types of frequencies that can be set like:

  • FCLK: Infinity Fabric Clock
  • MEMCLK: Memory Clock
  • UCLK: Unified Memory Controller Clock

Steps to set CPU Frequency using BIOS:

  1. Enter BIOS + Set Frequency mode to manual
  2. FCLK Frequency
  3. MEMCLK Frequency
  4. UCLK Frequency

Enter BIOS + Set Frequency mode to manual

The steps to change CPU Frequency using BIOS are:

  • Enter BIOS: While your system starts, press "delete" key to enter BIOS settings. The key varies across systems.
  • Once you enter BIOS, go to the following options to set Clock Frequency to Manual mode.
Advanced -> CBS -> NBIO Debug Options -> XFR Enhancement -> Manual

By default, it is set to "Automatic" so the options to set frequency values are not available. Once you have set the above option to "Manual", you can set different CPU frequency values.

FCLK Frequency

The next step is to set the FCLK Frequency. Follow the following steps:

Advanced -> CBS -> NBIO Debug Options -> XFR Enhancement -> FCLK Frequency

Enter the desired frequency value manually. Note that the values are in hexadecimal.

FCLK stands for Infinity Fabric Clock. By default, FCLK Frequency is same as RAM Frequency.

MEMCLK Frequency

The next step is to set the MEMCLK Frequency. Follow the following steps:

Advanced -> CBS -> NBIO Debug Options -> XFR Enhancement -> MEMCLK Frequency

Enter the desired frequency value manually. Note that the values are in hexadecimal.

MEMCLK stands for Memory Clock. MEMCLK Frequency is the frequency for DDR memory in the system. Memory clock on DDR4 memory is known as Data Rate. It has values like 6000 MT/s.

UCLK Frequency

The next step is to set the UCLK Frequency. Follow the following steps:

Advanced -> CBS -> NBIO Debug Options -> XFR Enhancement -> UCLK Frequency

Enter the desired frequency value manually. Note that the values are in hexadecimal.

UCLK means Unified Memory Controller Clock.

With this article at OpenGenus, you must have the complete idea of how to set up frequency of your system.