Do you have any software running that isn't Windows, the game, and the hardware drivers? Have you already unplugged everything that's non-essential like RGBLED controllers, USB hubs, bluetooth adapters etc?
Shitware like ASUS Armory Crate is often the culprit. If you installed Rivatuner Statistics server as part of the Afterburner install, that's also sometimes the culprit. Temperature monitoring software, RGBLED software, all kinds of utility/monitoring crap that's coded badly can cause hitching and stuttering like this.
If you haven't installed too much software yet, do a completely clean install of Windows and make sure you install NOTHING except your AMD or Intel chipset driver, your graphics driver, and the game. If you have stuttering then you know it's a hardware issue, start unplugging stuff until you reach t