Microsoft released the first-ever Patch Tuesday for Windows 11 last night with the new build version 22000.258 and apparently, the update makes the Level 3 (L3) cache latency for Ryzen CPUs even worse. AMD and Microsoft had earlier acknowledged that even the supported Zen-based processors, i.e., Zen+ and newer AMD CPUs, were exhibiting symptoms showing increased L3 latency that was affecting the performance of such CPUs in latency-sensitive applications like games, among other things. And the problem seems to have been aggravated with the new build. TechPowerUp says that the typical L3 latency for a Zen+ based Ryzen 7 2700X is around 10ns which was increased by more than 70% in the initial Windows 11 public release, as it measured around 17.1ns. However, after the Patch Tuesday update last night, the 2700X now gives an L3 cache latency of 39.1ns on the AIDA64 benchmark. That's nearly four times worse than what the CPU generally performs like.

Thankfully, there is a report that claims a Windows update, which will supposedly fix this L3 cache latency issue, is purportedly launching next week on October 19. The same report also adds that the CPPC2 problem will also be fixed with another update that will roll out a couple of days later on October 21.