There are some issues no doubt. However there are a few things you need to know before buying one.
The 5700 needs a psu that is 750W ('80 plus Gold' or '80plus Platinum') or higher (as you have other components that need power like the cpu, fans, hard drives, ram, etc). And, the PSU must have 2 separate pcie cables (not 2 pcie connectors on 1 pcie cable) in order to get the best experience. A low rate 650W '80plus' simply won't cut it and I've read a lot of reddit posts where people had to upgrade from 500w-650w in order to resolve:
-Stuttering/hitching (not all of it is related to psu though)
-Blackscreens/BSOD (most if not all appear to be related to psu)
If you absolutely can only afford a cheaper PSU get a 650W (which is recommended by most AIBs) but get a 80plus Platinum (not 80 plus).
If you are going from nvida to amd I would suggest a fresh win10 1903 install. As the drivers are based of off 1902 (which is WDDM 2.6 compatible). If you already have win10 1903 then use DDU in safe mode and remove all nvidia drivers 1st.
I would also suggest not trying to overclock Navi "yourself" right now. Just adjust the fan curve so that it doesn't throttle and set it to Auto Overclock. Let wattman boost it for you. I've found greater success letting wattman boost it then me trying to do it myself. Although Auto undervolting may yield better results for you.
Do these simply adjustments for your PC and you should have a pretty decent experience.
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Having said that I too had problems when I 1st had the card. I was using 19.9.3 and it was a complete stutter with low clocks/low gpu usage and just a horrible experience. I went to win10 1903, used Intelligent Standby List Cleaner and let Wattman's Auto Overclock do it's "thing" and I've been sailing along every since. I'm seeing well over 130+ FPS in most games I play at 1440p (although I don't crank IQ all the ultra...I found that 1440p alone makes a drastic improvement over 1080p that the IQ settings do very little to change).
I still haven't used sapphire trixx 7.01 (they updated it and provided no release notes from 7.00) to lower IQ and use RIS yet.
Also, you should be able to get the gaming bundle with your purchase. Well worth it IMO.
As long as you have a PSU that is 750W or higher and is rated Gold or better (Platinum/Titaninum) you should be good to go.
Having figured out my issue (as I was about to return the card) I can safely and confidently recommend it to you. Having said that there are a few 5700 I would suggest:
-Nitro+ (3 fans)
-Pulse (dual fan)
-Gigabyte (3 fans)
-RD (3 fans)