AMD announced last week that the performance of its processors running the new Windows 11 operating system was lower than expected. Although it was presented as a stable version, the new OS from Microsoft does not take full advantage of AMD processors and causes delays in their work. Interestingly, nothing like this was observed in Windows 10. But the recently released first cumulative update for Windows 11 made this problem even worse.
The first issue is associated with a threefold increase in L3 cache latency, which can reduce performance by up to 15% in some games. The second problem is related to the incorrect operation of the UEFI CPPC2 technology, which should distribute the corresponding processes among the fastest processor cores in order to achieve maximum performance.
TechPowerUp has measured the L3 cache access latency of the Ryzen 7 2700X. It turned out that in the first stable version of Windows 11, the latency was 17 nanoseconds, after installing the cumulative update from October 12, the latency increased to 31.9 nanoseconds. For comparison, in Windows 10, this latency is only 10 nanoseconds.
Microsoft has promised to fix the problem by the end of this month, while AMD, in turn, said it will introduce a new driver for its processors next week.