In my experience the biggest problem is something that cannot be solved by the kernel anyway, which is the microcode updates. AFAIK it's impossible to get that performance back by any means, even the mitigations=off flag cannot do that.
It is my understanding that these microcode updates get applied either by the operating system at boot time (applying the update every time you boot), or by the motherboard, if the BIOS was updated. As only this last method is "permanent" (or at least it requires you to downgrade your BIOS, something not always feasible) if you never upgraded your BIOS, I guess it should be possible to prevent the OS from applying the updates.
From my understanding, the microcode is the firmware of the CPU.
It's usually upgraded by a BIOS update or by Windows update. Windows update send driver/firmware updates, security patches or general updates if the vendor wants to support that way of distribution.
I think it's quite device specific and method specific whether the microcode can be upgraded and downgraded the same way.
The other poster is correct... microcode can be upgraded by BIOS update or Windows update, but the update doesn't persist on the CPU itself after a reboot (it has to be reapplied every boot, by either BIOS or Windows)
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It is my understanding that these microcode updates get applied either by the operating system at boot time (applying the update every time you boot), or by the motherboard, if the BIOS was updated. As only this last method is "permanent" (or at least it requires you to downgrade your BIOS, something not always feasible) if you never upgraded your BIOS, I guess it should be possible to prevent the OS from applying the updates.
From my understanding, the microcode is the firmware of the CPU.
It's usually upgraded by a BIOS update or by Windows update. Windows update send driver/firmware updates, security patches or general updates if the vendor wants to support that way of distribution.
I think it's quite device specific and method specific whether the microcode can be upgraded and downgraded the same way.
The other poster is correct... microcode can be upgraded by BIOS update or Windows update, but the update doesn't persist on the CPU itself after a reboot (it has to be reapplied every boot, by either BIOS or Windows)