My CPU is an Intel Xeon x5670  2.9 GHz, so it is not old. It must be able to run UEFI.

The problem with the T5500 is not so much Secure Boot but the fact that it is a 12 year old system with a pre-Generation 8 CPU. Per MS it is simply too old to be able to meet the Windows 11 system requirements.

While you can bypass the secure boot REQUIREMENT there are other requirements for 11 including directx 12 video card and 1280 X 720 monitor minimum.

https://docs.microsoft.com/en-us/windows/whats-new/windows-11-requirements

You have class 0 legacy bios.

https://uefi.org/sites/default/files/resources/Brian_Richardson_Intel_Final.pdf

UEFI SECURE BOOT Came from Windows 8 in 2012.

Your system is from 2007 with windows XP or VISTA sticker on the front.

Secure boot is more than just BIOS.

Systems that meet the UEFI 2.3.1 specifications provides the following benefits:

• Ability to support Windows 10 security features like Secure Boot, Microsoft Defender Credential Guard, and Microsoft Defender Exploit Guard. All require UEFI firmware.
• Faster boot and resume times.
• Ability to more easily support large hard drives (more than 2 terabytes) and drives with more than four partitions.
• Support for multicast deployment, which allows PC manufacturers to broadcast a PC image that can be received by multiple PCs without overwhelming the network or image server.
• Support for UEFI firmware drivers, applications, and option ROMs.

I have dirextx 12 and the maximum for my monitor is 1920x1080.

As far as I can see, the only thing I am missing is UEFI

Regards,

sonne.

The Xeon x5670 CPU was launched in Q1 of 2010 (that information here). That would place it well before the generation 8 CPUs. Also your CPU does not show up on the list of supported processors here.

@sonne  Microsoft require you to have an Intel 8th gen. processor or newer, or similar gen. of AMD CPU to be capable of running Windows 11.

From Microsoft:

1. Security. Windows 11 raises the bar for security by requiring hardware that can enable protections like Windows Hello, Device Encryption, virtualization-based security (VBS), hypervisor-protected code integrity (HVCI) and Secure Boot. The combination of these features has been shown to reduce malware by 60% on tested devices. To meet the principle, all Windows 11 supported CPUs have an embedded TPM, support secure boot, and support VBS and specific VBS capabilities.

I assume that Microsoft deem any older processor as not being capable of meeting these requirements.

Can you confirm that your CPU supports VBS, including the specific VBS capabilities that Microsoft requires for Windows 11?

It seems that the best solution is to buy a new PC latest Oktober 14th 2025.

Thank you for all your answers. I was too optimistic.

Sonne

I can sympathize as many users are in the same boat. It may be best to hold on until Windows 10 is no longer supported which is still 4 1/2 years down the road. And that date may well be pushed back.

As mentioned elsewhere, microsoft is strongly going to consider adding support for 7th gen and zen 1 amd.

The specs will change, and may change even more due to the beta testers using older computers > them getting more data. It's too early to draw the line, since it's officially shifting.

I do expect enough pressures and complaints that will expand support to :

W-21xx ( now not mentioned, absurdly 

Xeons e5 v4 and at least v3 

Core 7th gen ( already is happening )

amd zen 1 (already is happening)

One way to put it is that the T5500 has Legacy BIOS.  Legacy doesn't have Secure Boot and the T5500 won't be having UEFI BIOS.

@mazzinia

All Xeon W-21xx are officially supported by Windows 11:

https://docs.microsoft.com/pt-br/windows-hardware/design/minimum/supported/windows-11-supported-intel-processors

My T5400 with duo E5430, can install and run win 11,
but,
my T5500 with single E5645 can't install win 11

E5430 launch 2007 and E5645 launch 2010

can anyone explain why

Install using the media, correct ? ( is this a tweaked installation media to try to upgrade, or an untouched installation media to do a normal install ? )

yeh, i think they revised it after some weeks

https://www.google.com/search?q=bypassing+windows+11+tpm+check

>can anyone explain why

Enforced phasing out the partner's (Intel) old hardware.

In short - GREED for money. More money!!!! hahahaha!!