Like A.P. Hill above - I agree it sounds like it's a hardware issue and which is why I was trying to get more information on your system and experience to dive into it.
It could be one of two - but I'm going to bet money it's going to be #2.
#1 - could be a bad ram stick or both, it could also be a bad ram slot on the motherboard. HOWEVER - since you have dedicated graphics on your machine, I really want to save you the hassle. You can troubleshoot this really quick - if you realize that your machine runs slow or stutters at certain points - it's a sign it's a RAM stick or slot. And to test this, you test each stick individually and on different slots. Move from Slot 1 and 2, to Slot 3 and 4 and see if you have any issues.
But before you do all that above - again I'm betting money it's because of the AMD graphics card - here's why.
#2. On dedicated graphic systems, the graphics card takes the blunt processing power to run games. If you had an intel processor and an Nvidia Graphics card you would have to select the graphics processor to use for gaming in the Nvidia control panel. So I honestly believe it's the graphics card - it's either 1.) not able to reach it's bench mark or 2.) defective. If it's still under warranty I would try to get it replaced.
If it's under warranty - just get an RMA through the company you purchased the hardware from. If it's not under warranty - you can solidify the cause by Overclocking your system. If you overclock - you void the warranty of the machine which is why I said the first thing, if it's under warranty don't over clock your CPU. If it's not, you can try to overclock the system. If while you are overclock you experience issues with the frame rate right off the bat - it's a bad Graphics processor. It wouldn't be the CPU - the CPU has nothing to do with frame rate drop on a dedicated graphics card - however it will pick up the slack of the DDR4 (or DDR5) if it has to, but you'll notice it by the frame drop (if that makes sense).
I'll bet money cause I've seen it over and over again - it's the graphics card. If you get a new graphics card - I bet your problem would go away.