New AGESA Version Significantly Reduces Latency in RYZEN 9000 Series from 180 Nanoseconds to 75 Nanoseconds
Brook.X
Due to inherent design issues, AMD's ZEN processors have always had some latency-related problems, primarily due to AMD's Infinity Fabric interconnect. The communication latency between CCX (CPU Complexes) or CCDs (Core Compute Dies) tends to be higher, which is why AMD recommends using faster, lower-latency memory with ZEN processors for optimal system performance. However, this was not a fundamental solution to the problem.
Members on the AnandTech forums, while testing the 9950X, discovered that the new ZEN 5 had very high latency, with average latency times reaching 180 nanoseconds—more than double the latency of ZEN 4, especially between CCDs.
For comparison, the latency from one core to another within a CCD on the AMD RYZEN 9 9950X is 180 nanoseconds, while on the AMD RYZEN 9 7750X, it's only 76 nanoseconds.
This issue has been resolved in the latest BIOS firmware. AMD's newest AGESA version 1.2.0.2 has been significantly optimized, reducing latency on the AMD RYZEN 9950X to about 75 nanoseconds—a substantial decrease from previous latency times.
The developer behind Y-cruncher stated in discussions that AMD has clearly recognized the performance drop caused by latency, and the new firmware is the result of AMD's concerted effort.
However, the question arises: why was the latency so low in ZEN 4 but so high in ZEN 5? It turns out this was a mistake, as AMD made a series of parameter adjustments in ZEN 5. While these adjustments helped improve performance for most workloads, they realized such changes were detrimental for AMD's CPU complexes and thus retracted those adjustments.
Lastly, regarding AMD CPU performance issues, if you're using Windows 11, Microsoft also bears some of the responsibility.
Note: OEMs are expected to release their own versions of the AGESA 1.2.0.2 firmware compatible with their motherboards later this month. Users with AMD 9000 series processors can look forward to downloading and updating at that time.
