You're going to want to read the foundational published papers on operating system design. Especially kernel design and considerations. You can just Google any random graduate operating system class, and look at their reading list to get started.

I.e. https://www.cs.jhu.edu/~huang/cs718/spring20/syllabus.html

The big thing you want to look at is the different types of kernels there are, microkernels, monolithic kernels. How they divide memory, how they do IPC, how they incorporate drivers. All of these have different trade-offs.

BSD/Mac OS, Linux, NT/windows, xen/hypervisors... They all currently have different approaches, and they're all actually quite performant.

A while ago, process multiplexing, scheduling was had a huge impact on the perceived performance of a system, but now with multicore machines becoming extremely common well this is still important it is not as impactful.

Approaches to memory management, virtual memory, swapping to disk, the aggressiveness of this also has an impact on perceived system performance.

......

As you alluded to in your post, a lot of the perceived performance is not the operating system and kernel itself, but the user interface and extra services offered. Windows 11 is going to feel like a clunker for any retail user just due to all of the network driven advertisements incorporated which slow down the core interaction loop. If you click on the start menu and everything lags for a second will it pulls a new advertisements, you're going to feel that.

Start adding in background scanning for viruses, indexing for AI features, you're adding a lot of load to the system that's not necessary.

Linux encourages users to send patches while Microsoft is the sole company that can modify Windows.

It's very common to see patches from Google/Meta/Cloudflare/Amazon squeezing more performance for their particular use cases. That benefits everyone in the end.

Microsoft on the other hand is more concerned about its enterprise sales and overall profits. So they don't care that much. Windows 7 was horribly bloated, and they didn't address until Windows 8 because they had to, because they realized it was too bloated to run on their new tablet PCs so they had to do something about it.

Apple cares a lot, because their thing is energy efficient fanless netbooks, and phones, and tablets. macOS and iOS are very close in how they work, so Apple has all the incentive to keep it efficient because their software will also affect the hardware side of the business. Microsoft doesn't, it's the hardware partners that get stuck dealing with it.

The NT kernel is fairly good, it just doesn't get the attention it deserves. Microsoft mostly add features on top of older features, they never go in and be like "this sucks" and rewrite a feature, because that's very risky to do and may break millions of applications and affect their bottomline. Linux doesn't have to care about that.

I'd say, if Windows was open-source, we'd have some pretty solid Windows distributions because the community would care to go in and fix a ton of bottlenecks that aren't worth it for Microsoft as a company to even bother reviewing the patches let alone develop and test them. It's much more lucrative for them to release AI crap like Copilot than make Windows 10% snappier. Because most Windows users are corporate people that makes decisions based on marketing and business items than being an enjoyable experience. Less frustrated users? Nah. More productive employees with crappy AI features that barely works? Hell yeah 🤑

TL;DR: Windows sucks because of Microsoft's business interests don't require Windows to be that good, merely good enough.

As I'm sure you've gathered, this is a complex and nuanced discussion, but to me the biggest factors making Linux fast are:

• Absence of telemetry/data collection monitoring your use of the device
• Open source development model encouraging the entire world to contribute to make the Linux kernel better

There's something to be said where a consistent 5% performance improvement in a filesystem or process scheduler would be taken as a huge win. How would you even manage finding or contributing such a change to something closed source like Windows 11? Academics write papers about the kernel's performance and how it can be improved whereas I tend to think Microsoft takes more of a 'good enough' approach to such details.

I think both the Windows NT Kernel and the Linux Kernel are solid speedy parts of the OS. The main bloat is what's on top.

Windows seems to have progressively more bloated phases. Newer stock Windows programs are built from much heavier components.

1. There's the Win32 phase, which is super fast and lightweight. Few programs are still alive using this phase, WordPad (RIP) is one of them.

2. Then there's the broad Win64 phase, comprised of mostly Win Vista/7/8/10 parts. Word, Excel, and the old Outlook are examples of these programs. Slow upon their inception, they have become considerably faster due to better hardware, but still aren't very snappy.

3. And finally there's the new phase, Windows 11. Horribly bloated and laughably slow when pushed beyond the absolute basics. Examples include File Explorer, Notepad, Teams, and the new Outlook. Notepad is mostly fine, but even File Explorer takes multiple seconds to load basic things on midrange hardware. We all know how bad Teams is, and the new Outlook takes 30 seconds to launch and open an email even on high end hardware.

Much of the modern bloat comes from this latest phase, but somehow other parts of the system have seriously bloated as well, like all of the disk processes on startup and even the Windowing system, which used to be near instant on crappy hardware back in the Win2000 era, now takes up to a second on modern midrange hardware on 11.

Linux has fared better against the onset of bloat than Windows, which is the main reason why it feels much snappier and uses less memory. Despite this, you can still see Linux getting significantly heavier over the years, from the super lightweight Trinity Desktop to what we have now. But, web browsers powering many greedy tabs can easily out-bloat GNOME, to the point where Linux only feels slightly faster than Windows because everything is in a browser.

This may be a minor point, but I often think in discussions like these, people are talking about the entire OS rather than just the kernel. And while you can take a fully featured desktop ~~system~~ environment for a spin, and it's pretty good, a lightweight window manager is lightning quick.

If you stick to minimalistic apps for things like photo viewing, you can open folders with 1000s of images in thumbnail mode at incredible speeds, or enormous PDFs. Those are the types of tasks that seemingly slow W10 to a crawl.

In general I also have pretty good luck with stability on my machine. I don't find myself needing to kill apps that start misbehaving for unexplained reasons, except Firefox... But usually an update sorts it out.

Windows has an entirely different set of objectives. The coders have to layer on so many services that are insisted upon by marketing that no matter how optimised they make the kernel, it's always doing to be a little boat carrying far too much cargo.

There's also a lot of fairly reliable rumour that the Windows codebase is very messy. Evolved and complicated, supporting many obsolete things and has suffered from different managers over the years changing styles and objectives. We don't know for sure because it's proprietary.

But that said, I use both and find each good for different things. Windows is much more stable than it used to be, and speed is adequate for most things, largely because we've become used to buying better hardware every few years.

Windows also still runs software unchanged
from 20 or more years ago, while software on Linux has to be constantly updated to use new libraries and APIs, else it's considered "dead" and very soon will no longer run or even compile in its current form.

It has a lot of baggage that Linux doesn't need to worry about. Up until Vista, you could even still natively run 16 bit DOS software from the 80s.

Read The Cathedral and the Bazaar and you'll have your answer

This is just a theory, I don't have knowledge of the inner-workings of either Linux or Windows (beyond the basics). While Microsoft has been packing tons of telemetry in their OS since Windows 10, I think they fucked up the I/O stack somewhere along the way. Windows used to run well enough on HDDs, but can barely boot now.

This is most easily highlighted by using a disk drive. I was trying to read a DVD a while ago and noticed my whole system was locked up on a very modern system. Just having the drive plugged in would prevent windows from opening anything if already on, or getting past the spinner on boot.

The same wasn't observed on Linux. It took a bit to mount the DVD, but at no point did it lock up my system until it was removed. I used to use CDs and DVDs all the time on XP and 7 without this happening, so I only can suspect that they messed up something with I/O and has gone unnoticed because of their willingness to ignore the issues with the belief they're being caused by telemetry

It just doesn't have a ton of bloat. Windows is bloated while everything else is just normal

If there is free RAM, is there a reason not to use it?