If you've a cable modem with a Puma 6/7 chipset, it could possibly be the potential for said jitter. Sadly, I suffer from this issue and it annoys me to no end. Linking an old thread with more details about it. https://news.ycombinator.com/item?id=15781788
Just wanted to say that in linux you have extended attributes on files, check the man page on chattr. I believe the -i option makes files immutable.
I picked this little trick up watching a red team discuss how they set themselves persistence on the target system by making /etc/shadow immutable this way.. Fun bit is, root can't even remove the file until the flag is removed, and you can't see the immutable flag on the file unless you know what you are looking for via lsattr.
As someone who has recently bought into AMD from a long hiatus, I have to say they've come a long way since and I've been personally impressed with what I've experienced so far on the hardware side. That said, the reverse can be equally said on other matters pertaining to their business as well; more specifically their customer support pertaining to RMA's as of late. Mind you, this is all a personal anecdote so take with a grain of sand.