AMD has seemingly addressed the inter-core latency issues for its Zen 5 "Ryzen 9000" CPUs, with core-to-core Latencies seeing big drops & also leading to extra performance.
AMD Quickly Addresses Ryzen 9000 "Zen 5" Inter-Core Latency Issues With AGESA 1.2.0.2 BIOS Firmware, Massive Improvements
A few weeks ago, it was reported that AMD was working on a patch to improve the inter-core or core-to-core Latencies for its newly launched Ryzen 9000 "Zen 5" CPUs since various tech outlets discovered that the Latencies weren't optimal with up to 180-200ns Latencies when two cores from different CCDs communicated with one another. This led to sub-optimal performance & far worse results than what were seen on the Ryzen 7000 "Zen 4" CPUs.
It looks like AMD has patched this 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 & currently rolls out across a range of X670E, B650E, and B650 motherboards. This means that PC users who are running any of the updated motherboards with the Ryzen 9000 chips can leverage the new BIOS and see noticeable gains.
Anandtech Forum member, Det0x, managed to update his ASUS ROG Crosshair X670E Gene motherboard with the latest BIOS and posted results comparing the previous BIOS to the latest one using the CapFrameX core-to-core latency tool. The results are quite impressive. With the older BIOS, the user saw an average latency of 180ns between the CCDs and around 18-20ns when the cores communicated on the same CCD.
With the new BIOS, the average latency drops down by 58% to 75ns when communicating across CCDs and the inter-CCD latency remains the same at 18-20ns.
Now Inter-core Latencies shouldn't impact overall performance a lot since AMD's scheduler mostly leverages the single fastest CCD for gaming applications but in multi-threaded applications, it looks like the uplifts from this AGESA 1.2.0.2 BIOS fix are quite substantial.
Users are reporting that they are getting up to 400-600 points improvement in Cinebench R23. A few users who own the Ryzen 9 9950X also report that both CPU-z and 3DMark CPU benchmarks have seen noticeable uplifts and the best part is that the BIOS runs flawlessly without issues.
Some interesting information was also shared by the author of the Y-Cruncher benchmark who states that the latency issues were due to a change in the tuning parameters for Zen 5. Changes were made as they were showing results in the workloads tested by the engineering team but in synthetic benchmarks, they showcased bad results which is why AMD is now reversing its decision and rolling out this new patch.
The author was surprised that the patch rolled out this fast as the architects said it could take a while to get it out due to validation but it looks like ASUS has rolled out the update and it works as intended to resolve the inter-core latencies.
That was faster than I thought. I guess I can say this now that it has happened. One of the lead architects told me that the latency regression was because they changed a bunch of tuning parameters for Zen5. It helped whatever workloads they were testing against, which is why they did it. But now that the reviews are out, they realized that the change looked really bad for synthetics. So they were going to roll it back. But they said "it would take a while" due to validation.
I honestly didn't think it would happen for at least a couple months.
via Overclock.net Forums
Overall, this is great news for AMD Ryzen 9000 "Zen 5" CPU owners and the red team in general. Other manufacturers are expected to roll out their respective AGESA 1.2.0.2 BIOS updates later this month so we can see more users getting updated to the new firmware for a smoother and 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.