Windows 11 24H2 will block processors that lack the SSE4.2 instruction set

Alfonso Maruccia

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In context: Windows 11 has introduced more demanding hardware requirements for the installation and operation of the operating system. With the latest major upgrade on the horizon, Microsoft appears to be intensifying its efforts to ensure that the OS is incompatible with older components.

Windows 11 is approaching its third anniversary, and Microsoft is gearing up for the next major upgrade. Following the system requirement policy introduced in 2021, the upcoming Windows 11 24H2 release will discontinue support for PCs using certain older CPUs.

Microsoft has implemented a new "hard" compatibility block with Windows 11 Canary build 26058, requiring users to have a CPU with support for the POPCNT (population count) instruction to boot the OS. Another compatibility block has been identified in the latest Windows 11 preview build (26063), which introduces support for Wi-Fi 7 and officially requires proper support for SSE4.2 CPU instructions.

SSE4 is a SIMD (Single Instruction, Multiple Data) extended instruction set introduced by Intel in 2006 with its Penryn CPUs (Core 2). The initial SSE4.1 extended set included 47 new instructions, while a second instruction subset (SSE4.2) was first implemented in Nehalem-based processors released in 2008.

SSE4.2 instructions are designed to perform character search and comparison on two operands of 16 bytes at a time, which speeds up parsing of XML documents, accelerates CRC32 computation for certain data transfer protocols, and more. Any x86 CPU manufactured after 2008 should include support for SSE4.2 instructions, while processors released before the first generation of the Intel Core i5 and i7 CPUs do not.

The 26063 preview build has introduced a new "BlockedBYSSE4.2" value to the compatibility blocks stored within the Windows registry. Some users have attempted to install the OS on older PCs, confirming that the build cannot run on CPUs that lack SSE4.2 instructions.

At this point, it is unknown what Microsoft plans to do with forced SSE4.2 support in Windows' codebase. Previously introduced "soft" compatibility blocks of Windows 11, such as TPM and Secure Boot, were (and still are) easily bypassed, providing a cost-effective upgrade opportunity for owners of older PC hardware.

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I fail to see the relevance here as platforms from 2008 didn't have TPM 2.0 which is another "requirement" for the OS, so Microsoft is cutting CPU support for hardware they never really support to begin with? Big fat hairy deal.
 
I fail to see the relevance here as platforms from 2008 didn't have TPM 2.0 which is another "requirement" for the OS, so Microsoft is cutting CPU support for hardware they never really support to begin with? Big fat hairy deal.
TPM 2.0 is a "soft" requirement that is easily bypassed via rufus or manual methods.

This is a "hard" requirement that will render running on older hardware impossible.

Oh boy.
Are we just fearmongering at this point?
You severely underestimate how much old hardware is out there that people upgrade to 11 to keep it secure longer, especially outside the West.
 
The time to make and implement this policy was at the time Windows 11 was released.

Why would you want your customers to first install your O/S, and then tell them after the fact that you have decided to brick their machine?
 
TPM 2.0 is a "soft" requirement that is easily bypassed via rufus or manual methods.

This is a "hard" requirement that will render running on older hardware impossible.


You severely underestimate how much old hardware is out there that people upgrade to 11 to keep it secure longer, especially outside the West.
I know of an escalator that is still controlled by a windows 95 computer. All it needs to do is control the speed and direction of the steps. When Inwas talking to the guy about it he said it would cost millions to replace it because they would have to reverse engineer or just replace the motors and motor controllers in it.
 
Oh wait, there is a way to be left out by MS from the barrage of bug ridden updates? Sounds more like a pro than a con really.
 
TPM 2.0 is a "soft" requirement that is easily bypassed via rufus or manual methods.

This is a "hard" requirement that will render running on older hardware impossible.


You severely underestimate how much old hardware is out there that people upgrade to 11 to keep it secure longer, especially outside the West.
I know of an escalator that is still controlled by a windows 95 computer. All it needs to do is control the speed and direction of the steps. When Inwas talking to the guy about it he said it would cost millions to replace it because they would have to reverse engineer or just replace the motors and motor controllers in it.
If your CPU didn't have SSE4.2 you would not be using win11, period. there is no what-if beyond academic purposes. we are talking about core2 and phenom CPUs or older for crying out loud.
 
If your CPU didn't have SSE4.2 you would not be using win11, period. there is no what-if beyond academic purposes. we are talking about core2 and phenom CPUs or older for crying out loud.
Yes? I have several customers, who still use core 2 era hardware. It still works, and for their basic tasks there is no reason to move them to new hardware. When you deal with people on fixed incomes and limited requirements "just spend $500 on a new PC" isnt a valid answer. Especially as windows 11 runs on them just fine! This "requirement" is total BS, it doesnt need it to run now, and no new feature currently needs it either.

Let's try not justifying planned obsolescence, OK?

AS an addendum, place yourself outside of a rich western country. There are tens of millions out there, with "old" hardware, for whom even a cheap chromebook would be a year's salary. When 10 goes out of support, since 11 will be locked out, these people will continue using 10, creating a wonderful seedbed for botnets and AI powered scam systems. It took the better part of a decade to wipe out the XP botnets. It'll take just as long to wipe out the 10 botnets. So you are indirectly affected by this, even if you have all new hardware.
The time to make and implement this policy was at the time Windows 11 was released.

Why would you want your customers to first install your O/S, and then tell them after the fact that you have decided to brick their machine?
MS is hell bent on reminding people why they were so HATED in the 1980s/90s. Before the xbox 360 and windows 7 era.

You WILL replace your hardware when we demand! Think of the environment, specifically our bank vault! It needs more gold to keep it satisfied!
 
If your CPU didn't have SSE4.2 you would not be using win11, period. there is no what-if beyond academic purposes. we are talking about core2 and phenom CPUs or older for crying out loud.
I haven't used windows since 2021 and don't plan on it again. Just for funzies, I've been using a steamdeck as my main PC for the last 2 weeks. I have it docked and connected to a mouse and keyboard, but that hardly changes the purpose of the experiment.

Windows might as well be a dead OS
 
I haven't used windows since 2021 and don't plan on it again. Just for funzies, I've been using a steamdeck as my main PC for the last 2 weeks. I have it docked and connected to a mouse and keyboard, but that hardly changes the purpose of the experiment.

Windows might as well be a dead OS
The issue why they remain so popular is because most people are not willing to try something different as they are all too familiar with the OS. I had a hard time when I first trying a different OS, for example, shortcut keys that I am familiar with no working, etc. So it really depends on how willing are you to persist outside of the Windows OS, assuming you have spent a long time with it and rarely have exposure to a different OS. For me, I fall back to Samsung DEX which works well for office type work and light surfing.
 
The issue why they remain so popular is because most people are not willing to try something different as they are all too familiar with the OS. I had a hard time when I first trying a different OS, for example, shortcut keys that I am familiar with no working, etc. So it really depends on how willing are you to persist outside of the Windows OS, assuming you have spent a long time with it and rarely have exposure to a different OS. For me, I fall back to Samsung DEX which works well for office type work and light surfing.

The other problem is trying to go to Linux is daunting when you look at ALL the different distros out there, yes they are easily whittled down but if you have no clue what you doing, which all Linux newbies were at one time, it can be just easier to stay with what you know works even though you dislike it.
 
I switched away from Windows a few years back and switched to Linux for personal use, but I still have to use windows 10 at work. There is not one machine running windows 11 at work, windows 10 is still the main OS and from what I hear from administrators will be for the foreseeable future. We use a mixture of older and newer machines, the oldest is somewhere around 2010 and the newest is somewhere around 2015. It seems windows 11 on not in our future for now. In order to buy new machines to replace the ones we already have would cost to much $$$. If Microsoft gets there head out of their asses maybe they would see that what they're doing with these windows 11 requirements is a dead end road.
 
Yes? I have several customers, who still use core 2 era hardware. It still works, and for their basic tasks there is no reason to move them to new hardware. When you deal with people on fixed incomes and limited requirements "just spend $500 on a new PC" isnt a valid answer. Especially as windows 11 runs on them just fine! This "requirement" is total BS, it doesnt need it to run now, and no new feature currently needs it either.

Let's try not justifying planned obsolescence, OK?

AS an addendum, place yourself outside of a rich western country. There are tens of millions out there, with "old" hardware, for whom even a cheap chromebook would be a year's salary. When 10 goes out of support, since 11 will be locked out, these people will continue using 10, creating a wonderful seedbed for botnets and AI powered scam systems. It took the better part of a decade to wipe out the XP botnets. It'll take just as long to wipe out the 10 botnets. So you are indirectly affected by this, even if you have all new hardware.
MS is hell bent on reminding people why they were so HATED in the 1980s/90s. Before the xbox 360 and windows 7 era.

You WILL replace your hardware when we demand! Think of the environment, specifically our bank vault! It needs more gold to keep it satisfied!
"This "requirement" is total BS, it doesnt need it to run now, and no new feature currently needs it either." - That's just you making assumptions on the "features" MS is working on. It doesn't even need to be a feature, just removing bloated legacy support that NOBODY is using with windows 11 and streamlining the OS is more than enough.

You have Linux or older windows versions if you really want to use such ancient hardware.
 
Sounds like Microsoft's version of customer relations. It will surely aggravate some users - especially the less technical.

I keep dreaming that some day, Microsoft will finally realize that they don't own anyone's PC, and if they think they do, then they should pay users to upgrade their hardware so that they can run the Microsoft spyware OS on it.
 
So what! The TPM2 requirement postdates this one by about 10 years. This SSE4.2 requirement would only affect those using running hacked versions of Windows 11 on machines that were manufactured before about 2018.
 
So what! The TPM2 requirement postdates this one by about 10 years. This SSE4.2 requirement would only affect those using running hacked versions of Windows 11 on machines that were manufactured before about 2018.
So.... a HUGE number of PCs then?
 
"This "requirement" is total BS, it doesnt need it to run now, and no new feature currently needs it either." - That's just you making assumptions on the "features" MS is working on. It doesn't even need to be a feature, just removing bloated legacy support that NOBODY is using with windows 11 and streamlining the OS is more than enough.

You have Linux or older windows versions if you really want to use such ancient hardware.
Older windows versions do not maintain security updates. Are you suggesting everyone move back to 7? Much business software does not support linux.

Again, you are looking at this through the eyes of a rich Western man who can just dump $1000 on a PC because daddy MS tells you to.

Im not sure what tangent you are on about with removing bloated features. Maybe word your argument more clearly? Are you suggesting that mandating SSE4.2 is somehow de bloating the OS by removing a feature? Are you trying to say that MS will use SSE4.2 to streamline something (which isnt confirmed yet). Can you show anything in windows 11 that requires SSE4.2 to operate?
 
At least this is a REAL block (as in the OS and software is actually using it with no easy way around it) as opposed to the earlier "we are going to block it even though it's for optional features" blocks they had in the past.

As a Linux user I don't have to worry about this! (Much).. I did have ONE very old 32-bit system, it blew caps within a month or two of the Ubuntu 18.04 (last 32-bit version) going out of support. They have no plans to drop support for ANY 64-bit sytems. A few distros looked last year into raising the requirement to AVX2 -- but then realized (for when MMX was being added in the Pentium era) the distros have a facility called "hwcaps" for having side-by-side libraries and binaries installed. So instead they can ship AVX2 (or whatever newer instruction set) binaries side-by-side with fully compatible ones and the system will run the best one the CPU supports. So that is what they decided to do, and these couple companies that looked into this don't plan to re-visit it for 10 years -- whatever you're running now will keep running with them through at least 2033!

My dad was STILL running a Core 2 Quad as a daily driver untill less than 6 months ago (while I was down there we replaced it with a Coffee Lake system we picked up at a good price out of concern his 18 year old desktop would blow a cap or something eventually, and I don't live down there to do anything about it). Not wheezing along on XP or 7 or whatever, it was running Ubuntu 22.04, he was loading up 100-200 page documents in Libreoffice, heavy web surfing and video streaming, lots of printing and scanning, and Zoom conferences weekly! The video streaming and Zoom had brutally high CPU usage but it kept up on everything!

Indeed, I'm no fan of forced obsolescence and apparently neither is he.
 
Sorry, I didn't communicate well. My point is that the TPM2 requirement already excludes all those PCs that don't meet the SSE4.2 requirement and has since about 2018. I don't see the need for this TechSpot article.
Well, that was not a real requirement, it was a made up requirement required for one or two optional features that could be bypassed with a single install option or registry entry. This is a real requirement. I mean, you're right, this new requirement is blocking CPUs that were already formally unsupported, but now they are really unsupported.

Sure it's worth an article -- the Mac forums, people will routinely run older Macs with newer MacOS versions using OpenCore Legacy Patcher (OCLP). More recent unsupported systems, OCLP has to do very little, it was an artificial lockout. Somewhat older systems, they patch back in removed drivers. With the last several MacOS releases requiring AVX2, it was big news in that community as people found their older systems would truly be unsupported (although, they did come up with a super-kludgey fix, for now, to replace the AVX2-requring code with non-AVX2 equivalents.. oddly the x86/x86-64 emulator for M1 did not support AVX2 so they have an entire second set of x86/x86-64 macOS binaries still in the installer that don't require AVX and some OCLP addon patches those in.)
 
I believe the registry hack you speak of still does not circumvent the problem with the older machines not qualifying for annual feature updates. The registry hack would have to be repeated yearly I believe.
 
I believe the registry hack you speak of still does not circumvent the problem with the older machines not qualifying for annual feature updates. The registry hack would have to be repeated yearly I believe.
Not if done correctly. the ones I've deployed have functioned without issue, including downloading and installing new feature updates.
Sorry, I didn't communicate well. My point is that the TPM2 requirement already excludes all those PCs that don't meet the SSE4.2 requirement and has since about 2018. I don't see the need for this TechSpot article.
As Hwertz replied, the TPM requirement was a soft requirement that wasnt needed for system functionality for 99% of users. It's trivially bypassed, tools like rufus are 1 click.

Given that windows 11 is 10 with a new paintjob, its painfully obvious MS isnt doing this for functionality, but rather to tighten their grip on end users. Something I said several years ago.
 
Given that windows 11 is 10 with a new paintjob, its painfully obvious MS isnt doing this for functionality, but rather to tighten their grip on end users. Something I said several years ago.
Well, popcount instruction is great for trolling through text, and Microsoft LOVES to use large XML files to store their info (the amount of time Windows updates, windows file protection, and so on faff about reading and writing through giant XML files is rather surprising.) Really they should probably use a different file format for those files that have repeated data looked up out of them, data added to them, etc., but I do suspect they could be getting MASSIVE speed increases in XML processing using popcount, that they didn't just throw it in for the heck of it.

Or... it could just be that their compiler now emits popcount by default, and (given popcount is supported by all formally supported CPUs) they basically ARE just throwing it in for the heck of it (by not setting compiler flags to maintain compatibility with older CPUs.) I of course don't really know for sure.
 
This article is just making people hate on Microsoft for nothing.

The only people who this will have any effect on are those who are trying to install windows 11 on machines that often came standard with floppy drives.

Most of these machines do not have an update path to windows 11 in the first place. So a majority of users stuck on this hardware won't notice.


The argument that non-western people can't afford hardware that will support windows 11 after this hard block is put in place just shows how deeply out of touch some people are.

You can buy old hardware from China for under $50 that will be a drop in replacement into an old ATX computer case that provides a xeon server CPU (Ivy Bridge) with 16 cores and will run 11 (non-server).

The only places on earth where a years imcome is under $1000 dont typically have internet, reliable electricity, or plumbing for that matter. These places are few and far between. Most there are dealing with things far more pressing than if they can update windows 11 to the latest version.
 
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