NT is actually pretty great. The Windows GUI may have gone to shit, but the underlying kernel is great. I’d even argue that it’s ahead of Linux in many respects.
Linux is a slog comparatively, coming with hundreds of packed drivers for machines that stopped being sold a decade ago, unless you’ve tweaked your custom kernel config to only include drivers for your specific system. Windows has its fallback drivers, but most of them are downloaded on the fly rather than being precompiled into the kernel. This is part of why Nvidia drivers are such a pain to deal with on Linux.
The Windows scheduler and the Linux scheduler deal with processes just fine. Windows deals with hitting memory limits way better, but Linux has more flexibility to control the CPU scheduler. I also find Linux to be less efficient with file system caches, but that’s probably because Windows takes forever to complete I/O operations because of NTFS. Windows will fill your RAM with stuff you may need, while Linux happily keeps gigabytes of RAM unassigned (and act all surprise Pikachu when you actually request the browser that you open literally every time you boot your PC).
Linux doesn’t do antivirus, that’s the biggest difference. You get infected more easily, but you get faster I/O in return. This is especially the case when accessing tons of tiny files, like when booting the computer or programming. The load is relatively small when loading games and such.
I find Windows to be a lot snappier with my iGPU in power save mode, while Gnome and KDE are snapper when the iGPU is enabled. Video acceleration make or break Linux DEs much more than Windows in my experience.
I also find Bitlocker to perform a lot better than standard LUKS2, especially during the early boot process. The Windows bootloader isn’t restricted in its access to encryption acceleration functions the same way Grub is, so unlocking disks with similar cryptographic strengths at boot time is just faster on Windows. Plus, hibernating with encryption is possible without hacks and disabling security features in Windows, which is why it boots so fast (shutting down hibernates the kernel unless you need updates).
Linux is generally faster at updating (though using Flatpak GUIs would have you think otherwise), which is the biggest speed concern I have with Windows today. Perhaps it’s to make System Restore actually usable (something Linux can improve on) but it takes forever to install minor updates. Maybe it’s related to NTFS as well, which isn’t too great compared to the Linux alternatives on offer.
Windows is also terrible if you’re still running from a hard drive. With Windows 11 I’m pretty sure the devs abandoned HDD support all together with how slow it boots on spinning rust. A real pain when using virtual machines.
If you notice an immediate difference between Windows and Linux, it’s probably because you’ve recently installed a fresh copy of Linux. My Ubuntu and my Windows partitions boot in about the same amount of time. Give it a few years of gathering cruft and you’ll probably have an equally slow Linux install.