What is FCLK Frequency? What should your FCLK Frequency be?

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FCLK Frequency Meaning

To provide seamless, power-packed and ultimate performance, modern processors are made of interconnected subsystems like cache, CPU or the memory controller to enhance performance. The whole system is connected with Infinity Fabric, an architecture that is responsible for data transmission and control through the components of the processors. The Infinity Fabric is a communication bus, and it is controlled by the Infinity Fabric Clock or FCLK, a clock speed that dictates its operational performance. 

The Infinity Fabric connection architecture has been used in AMD microarchitecture, processors and GPUs since 2017. When the Infinity Fabric was introduced in AMD’s Zen 2 architecture processors, the FCLK was decoupled from the memory and is now controlled independently from the BIOS system by adjusting its speed.

This actually made RAM with low memory provide better performance. Now in the Ryzen 5000 processors of Zen 3 architecture, the FCLK frequency can be overclocked to 2000MHz (however, this is dependable) corresponding to the operation of 4000 MHz in RAM, which is Double Data Rate or DDR.

What is IF?

The Infinity Fabric was announced in April 2017 by Mark Papermaster, AMD’s SVP and CTO. It is a coherent high-performance fabric that can scale control and data flow across the linked components from die to the socket to board level. It is being used in AMD’s architecture for both CPU and GPU, which provides an additional speed and enhances performance. 

The two separate communication planes in the Infinity Fabric are the Infinity Scalable Data Fabric (SDF) and the Infinity Scalable Control Fabric (SCF). SDF has multiple connecting points which join the PCIe PHYs, memory controller, USB hub and other computation and execution units, and it is the primary means of data flow around the system and the endpoints of the connection. The SCF controls transmission of various system control system signals like tests, security, thermal and power management, and 3rd party IP.


Does FCLK impact RAM speed and performance?

The basic theory behind the increased speed of the RAM’s performance is the frequency of the data transfer rate. With FCLK, overclocking RAM has become easy, and it helps to modify specific parameters like timings and voltages, which help to operate the processors at greater speeds. So yes, FCLK does directly influence RAM speed. But altering clock frequency can affect the product warranty, stability, security, performance and life of the processor.


Are there any other clocks present in AMD Ryzen processors apart from FCLK?

  • UCLK: The UCLK is the frequency at which the UMC or Unified Memory Controller operates.
  • MCLK: It is the internal and external memory clock.
  • LCLK: It is the Link Clock at which the I/O Hub controller communicates with the chip.
  • CCLK: The Core Clock is the frequency at which the CPU core and the cache operate, it is basically the advertised frequency.

How is the FCLK frequency linked to the UCLK and MCLK frequency?


In Ryzen 3000 processors, the Infinity Fabric Clock and the Memory Controller Clock (UCLK) should be in 1:1 ratio of the system in order to give the best performance. The FCLK and UCLK are automatically clocked at a 1:1 ratio when the frequency is upto 3733 MHz. If the frequency is out of sync, like 4000 MHz FCLK and 3733 MHz UCLK or vice versa, then the ratio becomes 2:1, which introduces a latency penalty and performance loss. Keeping the frequency at a 1:1 ratio maintains the life of the processor.


The ideal ratio between the frequency on both FCLK and MCLK in Ryzen is 1:1 to get enhanced performance. It is recommended to use RAM at such a higher MHz speed that the Infinity Fabric can keep up. De-syncing can affect the performance of the chip, so it’s recommended to keep the timings tighter.


What should your FCLK Frequency be?

It is important to know that although FCLK is free to run at any speed, it doesn’t mean that you will use the max frequency because it can cause de-syncing and reduce overall performance. AMD itself recommended the users of DDR4-3600 to use FCLK at 1800 MHz for optimal performance. Basically, your FCLK should be half of your RAM Clock speed for better performance. FCLK, UCLK and MEMCLK are synchronized together, so it’s necessary that they sync properly and specifically, the 1:1 ratio should be maintained for optimized performance.

Should you increase your FCLK frequency?

No, and also yes; the answer totally depends on the users, as overclocking has certain costs. Ryzen CPUs are known for providing the best performance with RAM running synchronously with the Infinity Fabric Clock and the Memory Controller or the UCLK. But increasing the FCLK frequency can cause de-synchronization in RAM latency and cause problems in the form of blue screens.



What Is the Best RAM Frequency For Ryzen 5000?

With Ryzen 5000 CPUs and DDR4-4000 Ram, the FCLK frequency should be 2000MHz at a 1:1 ratio between the Infinity Fabric Clock and Memory Clock to provide the best and optimised performance. Although it is not a good practice to change the FCLK and set it at high frequency, there are a lot of AMD fans that increase the FCLK frequency to get the best performance.

Can Ryzen 5000 CPUs Reach 2000MHz FCLK?

Yes, it can easily reach a frequency of 2000MHz FCLK, but some other CPUs like Ryzen 5 5600X cannot reach 2000MHz, but it can hit only 1900-1800 MHz FCLK.

So what are the “Best” settings for Ryzen Infinity Fabric and memory?

For a DDR4 3600 RAM, the best settings are 1800MHz memory and 1800 MHz FCLK. It is true for all CPUs, as there are some CPUs that can’t reach 1900 FCLK, and there are fewer people who would want to raise the SoC voltage to see if it can reach 1900 MHz or not. And a 1:1 ratio between the highest FCLK and the highest memory frequency is the best possible configuration that you can use.


Read More

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  4. What Is SVM Mode? How to Enable/Disable It?
  5. What Does ‘Maximum Frequency’ in Resource Monitor Mean?
  6. What Does Erp-Ready Mean in Bios?


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