AMD Resolves Inter-Core Latency Issues for Ryzen 9000 Zen 5 CPUs
Introduction
AMD has addressed the inter-core latency issues for its Zen 5 Ryzen 9000 CPUs. The core-to-core latencies have seen significant reductions, leading to extra performance. The latest AGESA 1.2.0.2 BIOS update plays a crucial role in this improvement.
Background
A few weeks ago, reports indicated that AMD was working on a patch to improve the inter-core latencies for its newly launched Ryzen 9000 Zen 5 CPUs. Various tech outlets discovered that the latencies were sub-optimal, with delays up to 180-200ns when two cores from different CCDs communicated. This led to sub-optimal performance compared to the Ryzen 7000 Zen 4 CPUs.
BIOS Update Rollout
AMD has patched the intercommunication between the cores and CCDs in its latest AGESA 1.2.0.2 BIOS update. ASUS announced the first roll of this particular BIOS, which is currently being deployed across a range of X670E, B650E, and B650 motherboards. PC users with these updated motherboards and Ryzen 9000 chips can leverage the new BIOS for noticeable performance gains.
Performance Improvements
An Anandtech forum member, Det0x, updated his ASUS ROG Crosshair X670E Gene motherboard with the latest BIOS. Using the CapFrameX core-to-core latency tool, he posted results comparing the old and new BIOS versions. With the older BIOS, the average latency was 180ns between the CCDs and around 18-20ns for cores on the same CCD. The new BIOS reduced the average latency by 58% to 75ns for inter-CCD communication, while the intra-CCD latency remained the same at 18-20ns.
Impact on Applications
Although inter-core latencies shouldn’t impact overall performance significantly due to AMD’s scheduler leveraging the fastest CCD for gaming, the improvements in multi-threaded applications are substantial. Users report up to 400-600 points improvement in Cinebench R23, and noticeable uplifts in CPU-z and 3DMark CPU benchmarks.
Technical Insights
The author of the Y-Cruncher benchmark shared that the latency issues arose from changes in tuning parameters for Zen 5. These changes initially showed positive results in engineering tests but performed poorly in synthetic benchmarks. AMD reversed its decision, resulting in the new patch’s rapid rollout.
Future Updates
This development is excellent news for AMD Ryzen 9000 Zen 5 CPU owners. Other manufacturers are expected to release their AGESA 1.2.0.2 BIOS updates soon, offering a smoother and more stable experience with Zen 5 chips. The BIOS will also include the new 105W TDP mode for the AMD Ryzen 7 9700X and Ryzen 5 9600X CPUs.
