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Windows 11 Runs and Updates on 2006-Era Single-core Intel Pentium 4 CPU

A screengrab of Windows 11 running on an intel Pentium 4 661 CPU from 2006.
(Image credit: Carlos_SM1995 via Twitter)

Windows 11 has become one of the most divisive and confusing OS releases in recent history, despite Microsoft's efforts to announce and detail the system's capabilities, requirements, and differences relative to Windows 10. While Microsoft has accompanied communications on Windows 11 with stringent system requirements, there are already numerous ways to circumvent hardware limitations floating through the internet. The latest one such experiment, carried out by user @Carlos_SM1995 (via Notebookcheck), actually managed to install and run the OS on supposedly - according to Microsoft - incompatible hardware. What is this mysterious chip that can actually run Microsoft's latest OS? It's an all-powerful, single-core Pentium 4 661 CPU from 2006. It does feature Hyper-Threading, though.

To be fair to Microsoft, the system requirements refer to the hardware configurations that can run Windows 11 out of the box, and which can sustain all of its features - including security-focused ones, which were the basis for the Trusted Platform Module (TPM) requirement, and others. It certainly sounds fair to say that Microsoft would finalize its system requirements based on users taking advantage of all of the OS' features - and it really wouldn't make much sense to take any other course of action. Some of Windows 11 security features require specific hardware implementations to run smoothly when they're actually active - but naturally, should those features be disabled, the performance hit doesn't actually register for the end-user.

As such, we would say that the fault lies not on Microsoft; as it is one thing to run the OS as intended by the company. The other is to find ways to skirt some of those requirements by disabling features that one will not use - such as TPM, Secure Boot or Virtualization-Based Security (VBS) features. This is exactly what was done to run this particular Windows 11 OS build and the system even receives updates via the integrated Windows Update functionality, as you can see in the video below.

What Microsoft could have done, of course, is clarify which features can be disabled by users in order to achieve broader backward compatibility. But again, it doesn't seem like such a great idea for Microsoft to ship Windows 11 with security-facing features and then telling users how to disable them - that's just not a good IT security practice, period. There are naturally risks when disabling OS features -  especially security-centric ones, and Microsoft is playing it safe. Yet ultimately, this proves that users can still have control over what hardware they run their Windows 11 build - even if it just so happens that the hardware is a Pentium 4 from 2006.

  • King_V
    Pretty neat, though I'd dread running Windows 11 (or Windows 10, probably even Windows 7) on such a CPU.

    That said, we had a "What's the cheesiest system you've run Windows 10 on" thread. And, while I don't see myself adopting Windows 11 anytime soon, I'd probably look forward to a new thread here of the same type, but with regard to successfully (and semi-usably) running Windows 11.
    Reply
  • DeepCool_Phoenix
    Given that I'd gotten the same processor running on Windows 10, and the similarities with 11, I'm not super surprised. Glad it isnt hard-locked out at least
    Reply
  • Krotow
    It is more a proof of concept. In reality such CPU is already too slow for normal work even in Windows 7.
    Reply
  • great Unknown
    King_V said:
    Pretty neat, though I'd dread running Windows 11 (or Windows 10, probably even Windows 7) on such a CPU.

    That said, we had a "What's the cheesiest system you've run Windows 10 on" thread. And, while I don't see myself adopting Windows 11 anytime soon, I'd probably look forward to a new thread here of the same type, but with regard to successfully (and semi-usably) running Windows 11.
    I'm waiting for somebody to run it on a Commodore 64
    Reply
  • velocityg4
    Now to get it running on a 286 with 640K RAM.
    Reply
  • USAFRet
    King_V said:
    Pretty neat, though I'd dread running Windows 11 (or Windows 10, probably even Windows 7) on such a CPU.

    That said, we had a "What's the cheesiest system you've run Windows 10 on" thread. And, while I don't see myself adopting Windows 11 anytime soon, I'd probably look forward to a new thread here of the same type, but with regard to successfully (and semi-usably) running Windows 11.
    https://forums.tomshardware.com/threads/whats-the-oldest-and-or-cheesiest-system-you-have-win-10-installed-on.3516627/
    Reply
  • King_V
    USAFRet said:
    https://forums.tomshardware.com/threads/whats-the-oldest-and-or-cheesiest-system-you-have-win-10-installed-on.3516627/
    It must have been an interesting user experience if you ever hit a webpage . . lol

    I remember Linux with a P4 3.6GHz with hyperthreading. A webpage had the cooler roaring like a jet engine, and brought the system to its knees. PGDN took something like 10 seconds or so to respond.

    Ah, the joys of little video ads scattered about on a website...
    Reply
  • USAFRet
    King_V said:
    It must have been an interesting user experience if you ever hit a webpage . . lol
    Wasn't as bad as it would seem.
    Was my original Win 10 test box, Day 1 of the original Tech Preview.

    My current cheese wheel is an Asus Transformer T100HA.
    Win 10 Pro, 4GB RAM, Atom proc, 64GB eMMC drive.
    My travel device, fine for basic browsing or movies.
    Reply
  • Eximo
    Windows 10 on a Lenovo Ideacentre Stick 300, basically an Atom, 32GB of eMMC, one USB port, WiFi, and an HDMI out. I hardly use it, but it is an interesting toy for $90. If it didn't require a power brick it would be pretty neat as a little pocket computer, just add TV.

    I tried to get Windows 10 onto a Pentium D H/T without success, missing one of the key instruction sets. Seems like they used a similar processor. I will have to double check which one I tried.
    Reply
  • NightHawkRMX
    I have tried this.

    Minimum Pentium 4 that works is an LGA775 Pentium 4 HT 631. Alternatively, Cedar Mill Celeron Ds also work. I only have a Pentium 4 630 which lasks the feature set to work. None of the PGA478 Pentium 4s will work, not even the uncommon 64 bit ones.

    As for AMD side, I have done a fair bit of testing.

    AM2 CPUs are the earliest that work.

    Here is it running on my single core, single thread, Athlon 64 3800+. Its not exactly snappy.
    https://ibb.co/m85MJm8
    I tried getting it running on an original socket 462 Athlon 64 based Sempron and unfortunately they do not support an extension to x64 that is required for 64 bit windows versions past 8.0, so it just errors. I may be trying a workaround soon to see if I can disable the check for that, but it probably won't work.
    Reply