Those with AMD Ryzen chips in their PCs may want to avoid upgrading to Windows 11 for the time being.

Both AMD and Microsoft have admitted that Windows 11 can cause performance degradation of as much as 15% when using this processor. The news was announced in a blog post (discovered by Tom's Hardware) in which the companies explained that AMD CPUs "may exhibit performance degradation in certain applications when running Windows 11."

One of the affected features is measured and functional L3 latency, which could increase up to 3x. Clearly, this is going to affect applications that are particularly dependent on access to memory, such as games.

According to AMD, the affected applications are affected by 3-5%, but for some outliers, including popular eSports games, this figure increases to 10-15%.

Also affected is AMD's "preferred cores" feature, which allows applications to be assigned to faster cores on the chip as needed; upgrading to Windows 11 may prevent this feature from working properly, especially on chips with more than 8 cores and TDPs above 65W will cause a noticeable performance drop, especially on chips with 8 or more cores and TDPs above 65W.

According to AMB, this issue affects EPYC and Athlon chips, as well as all Ryzen CPUs currently supported by Windows 11. Clearly, one should be aware of this issue before attempting to upgrade a PC to Microsoft's latest OS.

Both companies are actively investigating the issue and plan to release updates to fix the relationship between Windows 11 and AMD hardware. These updates are expected to be available this month, but details have not been disclosed.

In the meantime, however, Windows 10 should continue to operate normally. In other words, you may want to avoid upgrading your OS until all the major bugs are worked out. In fact, for those who don't have AMD hardware and don't need access to Windows 11 right away, this is pretty solid advice.

If you find Windows 11 to be far more trouble than it is worth today, you can downgrade to Windows 10. However, as one Tom's Guide staffer discovered, upgrading back to Windows 11 may cause some problems. Therefore, it is best not to go back and forth between Windows 11 and Windows 10 if you can help it.