AMD Ryzen CPUs get unexpected performance boost thanks to Windows update

The 24H2 update for Windows 11 users contained a nice surprise for AMD Ryzen users who saw CPU performance get a big boost.

Many AMD users watched the tech news, waiting to read the performance figures for the brand new ‘Zen 5’ Ryzen 9000 processors. Many were surprised at the lackluster numbers that then emerged from benchmarks, especially when compared to the official figures from AMD.

As it turns out, this gap between expectation and reality might have been due to a bug in Windows 11. A bug that has now been fixed thanks to the new 24H2 update.

The bug does not only affect the new Zen 5 CPUs, but has also caused older Zen 4, and possibly even Zen 3 models to suffer a performance hit.

According to YouTuber and analyst Hardware Unboxed, AMD Ryzen 7 7700X and Ryzen 7 9700X benefited from performance increases of 10% and 11% respectively. Performance gains of up to a whopping 36% were shown for some CPUs.

The bug is thought to relate to ‘Branch prediction code optimizations’. Branch prediction involves a CPU predicting what code will need to be loaded in next by the software and having that code ‘on hand’ loaded into the cache ready for execution.

Windows had been preventing the AMD CPUs from properly utilising branch prediction, slowing date the rate at which code could be executed by the CPU. Zen 5 is said to take greater advantage of branch prediction, which is why Zen 5 chips appear to benefit the most from the update.

AMD was able to enable these branch prediction options by using their greater administration privileges. This accounts for the difference in performance reported by users versus the official figures from AMD.

It is not known why AMD chose to keep the existence of this bug quiet for so long, but the boost in performance will no doubt benefit Team Red when Intel’s Arrow Lake-S desktop CPUs are released.