Windows 11 has introduced a significant change with its latest 24H2 update – it appears to be incompatible with older machines. While it has always been known that you cannot install Windows XP on a 386 or Windows 95 on an original IBM PC, the goalposts seem to have shifted for Windows 11.
The reason behind this incompatibility lies in the POPCNT CPU instruction. Various Windows 11 system files, including the kernel and USB XHCI drivers, contain this instruction, as shared on Twitter by TheBobPony. Machines with CPUs that are unable to run this instruction will consequently be unable to boot Windows 11.
POPCNT was initially introduced in AMD’s Barcelona architecture in 2007, followed by Intel’s Core processors in 2008. This instruction is used to count set bits in a word, but its absence poses a challenge for older CPUs.
Therefore, computers with outdated CPUs will no longer be able to run the latest version of Windows 11. It is possible that Microsoft has enabled more modern CPU instructions during compilation, rendering older hardware incompatible. Given that affected hardware is over 15 years old, it is likely that Microsoft has made a deliberate decision to cut off these machines from using the latest version of its operating system.
If you are running super-old hardware, it is advisable to keep a close eye on Windows updates. It is unfortunate for those who will be affected, but this phenomenon is not unprecedented.
Share your thoughts on whether you will be affected by this incompatibility in the comments below.
We extend our gratitude to Stephen Walters for bringing this information to our attention.
Windows 11 Incompatibility with Older Machines: FAQ
Q: What is the main change introduced in Windows 11 with its latest 24H2 update?
A: The main change introduced in Windows 11 with its latest update is that it appears to be incompatible with older machines.
Q: Why are older machines unable to run Windows 11?
A: The incompatibility lies in the POPCNT CPU instruction. Various Windows 11 system files contain this instruction, and machines with CPUs that are unable to run it will be unable to boot Windows 11.
Q: What is the POPCNT CPU instruction used for?
A: The POPCNT instruction is used to count set bits in a word.
Q: When was the POPCNT instruction introduced?
A: POPCNT was initially introduced in AMD’s Barcelona architecture in 2007 and Intel’s Core processors in 2008.
Q: Why can’t older CPUs run the POPCNT instruction?
A: Older CPUs do not have support for the POPCNT instruction, which makes them incompatible with Windows 11.
Q: Will Microsoft enable more modern CPU instructions during compilation?
A: It is possible that Microsoft has enabled more modern CPU instructions during compilation, which could render older hardware incompatible with Windows 11.
Q: Is it likely that Microsoft intentionally made older hardware incompatible with Windows 11?
A: Given that the affected hardware is over 15 years old, it is likely that Microsoft has made a deliberate decision to cut off these machines from using the latest version of its operating system.
Q: What should users with super-old hardware do?
A: It is advisable for users with super-old hardware to keep a close eye on Windows updates to stay informed about the compatibility of their machines.
Q: Is this incompatibility unprecedented?
A: No, this phenomenon is not unprecedented. In the past, certain operating systems and software have had compatibility limitations with older hardware.
For more information about Windows 11 and its system requirements, you can visit the official Microsoft website: Windows 11 Official Website.
The source of the article is from the blog procarsrl.com.ar