Regarding Avast & Malwarebytes, see: https://forums.malwarebytes.com/topic/200324-exclusions-for-avast-users/
All shields of malwarebytes are off. As I said I only use it as a manual scanner. I even deactivate the trial and completely make it free.
It's also not a problem with the shields, I think. I have noticed only so far that the settings in full virus scan is reset to defaults, haven't checked the shields at that time but I have not changed those.
Unless something goes wrong during the install of malwarebytes , otherwise I don't think it has much effect, or it's because of the forced free trial? . If it is malwarebytes that would imply that it messes with avast files and settings. And I have always used both of them in the past. But if it was related to files, not sure if factory reset should fix the speed then, which so far it seems it does.
I should note that there's nothing installed on the pc besides those 2 things.
I do remember that the last time this happened was in July and now it happened again a few days ago with a fresh install of Windows.
It's either an avast update or malwarebytes that does something to the settings and avast. And I do want to figure it out as it's bothering me too much as to if it could be something malicious or not.