Amd confirmed that the upgrade of windows 11 is a major bug: the CPU speed is reduced by 15% at most, and the patch will be released soon

Time:2021-10-27

The highly anticipated windows 11 was officially launched on October 5, but then many bugs were revealed. Just now, amd confirmed that upgrading windows 11 will reduce the performance of AMD ryzen dragon game by 15%. At present, AMD and Microsoft said they would solve the bug by issuing a patch.

According to AMD, when used with the windows 11 operating system, it may reduce the performance of all its processors compatible with windows 11 in some applications. For example, in E-sports games, the extreme abnormal value of performance degradation is as high as 10-15%; For applications, amd says its performance impact is also 3 – 5%.

Amd said that this bug will affect every AMD ryzen CPU supported by windows 11. That is, all Zen +, Zen 2 and Zen 3 CPUs, including ryzen 2000, ryzen 3000, ryzen 4000 and ryzen 5000 processors, will be affected.

In addition, AMD epyc and some newer Athlon chips selected by the company’s data center will also be affected.

(you can see the complete list of CPUs affected here. Amd indicates that each amd chip in its best game CPU list is included:
https://docs.microsoft.com/en…*ivFEQ&ranSiteID=kXQk6.ivFEQ-.iZIwsDA.sjl4UW1rlQWVg&epi=kXQk6.ivFEQ-.iZIwsDA.sjl4UW1rlQWVg&irgwc=1&OCID=AID2200057_aff_7593_1243925&tduid=%28ir__o9eqgapktgkf6xz9sap6wurx6u2xr6csnyiol2kn00%29%287593%29%281243925%29%28kXQk6.ivFEQ-.iZIwsDA.sjl4UW1rlQWVg%29%28%29&irclickid=_o9eqgapktgkf6xz9sap6wurx6u2xr6csnyiol2kn00

Amd consultant said that the problem may be attributed to two types:

First, the L3 cache latency of measurement and functionality can be increased by about three times, which means that you can see the impact of measurement utility, which will lead to the actual performance degradation of games and applications. This bug will affect applications that are sensitive to memory subsystem latency, resulting in a performance reduction of 3 – 5%. This problem also leads to 10 – 15% performance degradation outliers in games “commonly used for E-sports”, which is not surprising because games are very sensitive to memory and cache latency.

In addition, AMD’s “preferred kernel” function directs single threaded applications to the two fastest cores on the chip, which may not work as expected. This will mainly affect the performance of light threaded applications. Amd said that this performance degradation may be more obvious in chips with 8 or more cores and TDP rated power of 65W or higher.

Although amd said that it had no more information to share about the above problems, in a latest announcement, amd said that it was “actively investigating these known problems and solving them through software updates” with Microsoft on the above bug, and would update its announcement when it was available.

Amd suggests that customers who encounter problems can “continue to use the supported version of windows 10”, which seems to mean that it is unwise to upgrade windows 11 before the problem is solved.

Amd said that it is expected that the windows update will solve the L3 cache problem. At that time, the software update will also solve the problem of the preferred core technology of UEFI cppc2, which may be realized this month.

The following are the test results of foreign media on this problem:

  • Tested and running L3 cache latency may increase by about 3 times.
  • Applications that are time sensitive to memory subsystem access may be affected.
  • The expected performance impact of the affected application is 3-5%, and there may be 10-15% outliers in common E-sports games.
  • UEFI cppc2 (“preferred kernel”) may not give priority to scheduling threads on the fastest processor kernel.
  • Applications that are sensitive to the performance of one or more CPU threads may exhibit performance degradation.
  • In 8-core processors larger than 65W TDP, the performance impact may be easier to detect.

It is reported that Microsoft has officially launched windows 11 on October 5. The new system will bring users a more concise appearance, and has made new upgrades in touch experience, voice input, collaborative editing, application development, barrier free enhancement and games. Qualified windows 10 pcs can be upgraded free of charge.