It's a common issue with tens of thousands of people, game runs like crap. so much so in fact blizz forums had multiple 26 page posts there were "closed" and now deleted. Issues never being resolved.
Google it. You guys in denial/dont care if stuttery/used to it/dont notice it/w.e will find several lengthy posts on several different forums complaining of the same issue, you will also find a ton of useless information from people trying to help fix the issue/denying it exists/blaming hardware/w.e, but it NEVER gets resolved unless the issue was found not just in D3 but ALL games, issues like bad ssd, ram, OC, software issue, etc.
Go do some work and make a list of games that NO one complains about, buy the game and find out hey it works great.
Make another list of games that people complain about, buy the game and experience the same issue.
Come back here and honestly tell us the issue is hardware or software. HINT skyrim, D3, Rift, POE, <-- anyone else want to add to the list ?
It's poor optimization/bug/coding with client and or server.