Fake news... so much fake news. And I mean that because of the irrational focus on Microsoft in this thread. The specific take on Windows 11? Please... this issue is so much larger than Windows 11.
There is NOTHING, let me repeat that NOTHING software can do to compensate for a fault in hardware design. There are mitigations of course, and those mitigations in this space come with MASSIVE performance problems.
We can all expect speculative execution vulnerabilities to continue to be a thing for a very long time. The difference between old machines an new ones is the Intel chips Gen8 and younger, and the equivalent AMD CPUs have flexible enough microcode implementations they can be patched via firmware update. Which not only mitigates the problem in theory, but does so at less of a performance penalty. This is a fact of life because speculative execution is the source of all CPU performance gains since the 486! Let that sink in... there are people reading this too young to have ever used a CPU that doesn't have this issue!
If Microsoft pulled a Linux, they'd be taking a black eye for a huge CPU performance hit and everyone would be complaining their machines are slow. If you did any bench-marking on any Linux platform that has these mitigations in place because you have a vulnerable CPU, you'd have felt the performance loss too. It's not small.
I fear this problem is like Row Hammer, and unsolvable... but we'll see how it works out. In the meantime for the love of all that is good in the world, update your BIOSs.
This article is actually pretty good at going over it all:
https://www.tomshardware.com/news/intel-cpus-performance-hit-spectre-v2-migitations
