While going through my backups today and contemplating whether I should roll back because of slow performance, I inadvertently discovered that all my Power and Performance settings, all of which I had set to high Performance, had reset themselves.

After reinstating all the performance settings, my computer seems to act the way it did before Windows Update (not sure exactly which one), and I no longer feel a need to roll back. Just something simple to check if your maching underperforms after an update.