What motherboard are you using? You will need one of the following:
Asus Crosshair V Formula-Z
Asus Sabertooth 990FX/R2.0
Asus M5A99FX PRO/R2.0
ASRock Fatal1ty 990FX Professional
ASRock 990FX Extreme9
ASRock 990FX Extreme6
ASRock Fatal1ty 970 Performance/3.1
Actually I have the ASRock 970A-G/3.1. It's made to support FX-9xxx processors so it should not be the problem here.
What are the temperatures when running Prime95? I've been running mine on a Crosshair V Formula-Z for years and have never had issues. I am using a Noctua NH-D14 air cooler for it.
With the Corsair's H115i temps are below 60 celsius. I think that even if the temps would be too high, it wouldn't cause error in Prime. I had the fx-6300 before this and it didn't fail a single stress test because of temps, even though the temps were much above the "safe limit"
I've been dealing with this POS processor for close to 3 years now. It is completely unstable at stock clock speed. After switching out parts for months after my initial build, one of my friends suggested underclocking it to see if it would be stable. Underclocking through BIOS would cause immediate freezing so I resorted to using AMD Overdrive. Underclocking it to 4200 MHz using AMD overdrive fixed the random freezing I was having.
Everything was going fine. It was still powerful enough for everything I was doing even with it underclocked so no big deal - until Windows 10. For some reason with Windows 10 when I do a fresh start up the login screen flashes white and black. This happens until I the flashing stops long enough for me to restart from the login screen. Then my computer is fine until my power goes out or something causes me to have to do a fresh bootup.
This would even be satisfactory for me because I usually keep my computer running all the time anyway, but now anytime I need to do a Windows up my system freezes in the middle of it and then I have to go through the update rollback process.
I don't know if anyone will even see this, but just now after losing power it took me 30 minutes to get through my white/black screen flashing boss level of a login screen to restart, and I ended up coming straight here to post my frustrations.
TLDR: Try underclocking to 4200 MHz using AMD Overdrive and your freezing issues might go away.