System locking up/unstable after upgrading to FX-9590

[Kupari]

Just upgraded to this CPU yesterday from an FX-6300 and I've had nothing but issues. My system will totally lock up at random and won't respond to any keyboard or mouse input at all, so I have to hit the reset switch. It doesn't seem to matter what I'm doing, it happens while gaming, just browsing the web etc. I'm actually writing this on my tablet because I can't trust my machine to stay stable long enough to finish the post. My specs are as follows:

AMD FX-9590 Black Edition (I haven't done any overclocks yet)
Corsair H55 liquid cooler
Gigabyte 990FXA-UD3 mobo
XFX R9 290 Black OC 4GB
8GB RAM
750W Superflower PSU

Any ideas?

 

[Kupari]

Quick update on this. I've been running a HeavyLoad stress test for 4 and a half hours now, and the system hasn't locked up yet. Max temp is 72c, with the average being mid-60s. I'm going to keep running the test and I'll see how I get on.

 

[Kupari]

But what did you do...

Nothing at that point. I've updated the BIOS too and that seems to have improved things. Just watching and waiting now.

 

[Kupari]

So it went from completely unstable, using a tablet to post on here to now working fine with little changes made?

Mate, I'm as confused as you are.