@johnny101 Windows Update is CPU intensive for performance reasons, because it's usually designed to run only when you step away from your computer. I have heard that this is due in part to Windows compiling .NET components from source directly on your computer. It could also be poorly written file syncing code, like the problems that Google Drive has. Meanwhile rsync runs relatively performantly on a native Windows system (i.e. a file sync operation that would take weeks on Google Drive would take 1-2 hours with rsync, with a fraction of the CPU utilization).

Regarding power usage in general: Assuming you do basic stuff like local account only, uninstall OneDrive, remove the weather widget, etc: I would argue that the bottleneck still isn't NTFS. Windows is simply doing more "stuff" in the background, and the issue is compounded by OEM background services. These services are already loaded into memory, so they don't have to read from the filesystem that much. Even assuming these background services are doing mostly nothing, they probably aren't optimized very well.