AMD has confirmed that the Ryzen 7000 processors will be compatible with DDR5 memory at 5,600 MHz, although thanks to the overclock they will be able to work without problems with memory modules that reach higher frequencies. However, we must bear in mind that, as was the case with previous generations of Ryzen processors, we will have a maximum ceiling that we will not be able to exceed if we want to maintain the 1:1 mode, and that ceiling will be 6,000 MHz.
In case someone has gotten lost, I remind you that the importance of the 1:1 mode is very great, but to understand it we must be clear about how AMD’s Ryzen processors work. These have three key elements:
- The Infinity Fabric Clock (FCLK), which determines the speed at which the CPU cores can communicate with the other chiplets, including the CCD units and the I/O unit. In the Ryzen 5000, its maximum frequency is 2,000 MHz, so it can work with RAM at a maximum of 4,000 MHz while maintaining a 1:1 frequency ratio (RAM is “double data rate”).
- The Memory Controller (UCLK), which determines the maximum speed at which the memory controller can work.
- The Memory Clock (MCLK), which is the speed of the RAM memory that we have installed.
If the RAM is running faster than the FCLK can tolerate, it will switch from 1:1 mode to 1:2 mode. When it works in 1:1 mode, the FCLK will work at 2,000 MHz and the rest of the elements will be perfectly synchronized, which means that if we have RAM installed at 4,000 MHz, it will maintain that speed. Nevertheless, if the 1:2 mode were activated the speeds would be reduced by halfso the FCLK would run at 1,000 MHz and the RAM at 2,000 MHz.
With all of the above in mind, we already know why it is important to know that the Ryzen 7000 will be able to work in 1:1 mode with DDR5 at a maximum of 6,000 MHz. This means that mounting faster RAM would not make any senseand that it is likely that the optimal point to achieve good performance with these processors is in the DDR5 at 5,200 MHz. On the other hand, taking into account that the Ryzen 5000 supported 4 GHz RAM with a 2 GHz FCLK I deduce that the Ryzen 7000 will have an FCLK at 3 GHz.
Taking a look at the previous generations we see that AMD would have achieved an important jump with the Ryzen 7000, since they will be able to use DDR5 memory at 6,000 MHz in 1:1 mode, while the Ryzen 5000 peaked at DDR4 at 4,000 MHz, and the Ryzen 3000 did so at DDR4 at 3,800 MHz. , the optimal point of both began in the 3,200 MHz with low latencies.
I remind you that all this is a consequence of the design of the Ryzen processorswhich use a modular architecture with interconnected chips. That’s where the Infinity Fabric Clock comes in, is that it is key to the correct communication of all the chiplets. In the case of processors with monolithic designs, this element does not exist, since we have a single chip (a single package).