The interconnection bus of the AMD Ryzen processors depends directly on the frequency of the RAM memory, 'demanding' memories with a fairly high frequency.
The new AMD Ryzen processors are based on the Zen architecture, an architecture developed from the ground up, to offer a product that would be competitive and compete against Intel again. These processors incorporate the Infinity Fabric bus technology. Infinity Fabric technology is HyperTransport technology, an internal processor interconnect technology, developed by AMD. This technology has been implemented in the new AMD processors to interconnect the different CCX assemblies with the other components integrated in the processor.
Internally, the processor has a series of elements that need an interconnection, such as the processing cores, the PCIe modules and the Southbridge. As AMD has commented, this connection bus has been developed in such a way that it is synchronized with the frequency of the memory clock. We know that RAM has a very important weight in the performance of the processor, even more than in Intel processors. Now, the pieces fit together, since the processor connection bus depends very directly on the speed of the RAM.
The Infinity Fabric interconnect bus is a 256-bit bidirectional connection interface, used in the Zen architecture, but will also be present in the Vega architecture. The frequent dependence of this bus so directly on RAM means that performance will improve at higher frequency. This means that if we use 2600MHz RAM, the bus will work at half this frequency, 1300MHz. Of course, this implies that the faster the RAM, the better the interconnection bus will work because it will work at higher frequencies.
Now we understand the initial performance problems of the AMD Ryzen, which due to BIOS problems, reduced the frequencies of the RAM memory and the processors had such great performance losses. The latest updates already support more clocks and RAM and AMD AMP profiles (AMD's version of the Intel XMP), therefore you should see quite a significant performance improvement.
Source: techpowerup
Good article !
It seems to me that AMD should make the interconnection a little independent to avoid the loss of performance that in some cases becomes very evident and avoid looking like a bad product!