The close relationship between AMD Ryzen CPUs and their RAM in terms of performance makes it important to know what kind of memory we can give our system to get the most out of it. That’s why we’ve compiled a list of the best memory modules you can find to get the most out of your processor.
The choice of RAM may seem completely unimportant when buying a PC, but there are two features that have always been at odds. The latency of the memory on the one hand and the bandwidth on the other depends on the system we want to build, so we have to consider how the interaction between RAM and AMD Ryzen affects the performance.
The relationship between AMD Ryzen and its RAM:
To understand how system RAM has to do with performance from Ryzen CPUs, we must begin with the fact that the integrated memory controller, IMC, and scalable data fabric, the clock speed of North Bridge, equals the clock speed of system memory. Is, which is not equal to the speed of transfer.
In other words, if we combine DDR4-2400 memory with a transfer rate of 2,400 Mbps, but with a speed of 1,200 MHz, it will not only communicate with RAM at that speed, but also internally. Will do the same On the other hand, if we replace it with high speed type memory, such as DDR4-3200, the speed will go up to 1,600 MHz and if we go even further, like DDR5-4800, then to 2,400 MHz.
We must keep in mind that Ryzen cores are grouped into blocks of 4 or 8 cores, depending on the generation of architecture, called CCDs. In order to communicate between the hubs of different groups, they have to go through the central SDF, which is affected by the speed at which we run the RAM attached to it. Therefore, inserting technically slow memory affects the performance of the system.
What is Geardown Mode?
Theoretically, it should not be possible to go beyond the maximum speed supported by IMC, but AMD implemented support for DDR4 Geardown mode in its Ryzen. Which means if you plug in the DIMM faster than the on-board memory controller, then what IMC does is reduce the clock speed by half. The reason why this happens is understandable if we look at each clock cycle as a period of time in which the RAM and the controller have to match the signal to communicate and this is only achieved at these frequencies. Can be multi levels of each other.
Geardown mode and RAM speed in AMD Ryzen:
This happens in all processors and memories, we must remember that the difference in AMD Ryzen is that the North Bridge also adopts this speed, so although you will be able to keep RAM faster, it affects the performance of our AMD Ryzen. So we have to keep in mind which of the fastest types of RAM is supported by each generation of these processors.
The Ryzen 1000 supports DDR4-2667 as its maximum clock speed.
The 2000 series, despite being based on a slightly improved version of the first generation Zen Core, increases RAM speeds to DDR4-2933.
The Ryzen 3000, 4000 and 5000 based on Zen 2 have an IMC with a maximum speed of 3200 MHz.
Remember, this does not mean that these processors do not support high clock speeds, but their use increases the internal delay and it is detrimental to CPU performance, but it is not. If you have an APU, no extra waiting. It doesn’t matter if you can get good bandwidth for iGPU.
