There should be enough power ,but the usage of 4 RAM sticks could be tricky.
After you let it clear itself install only one RAM module.You should in fact test them all.I would go for a kit with 2 modules myself for the future.Bad /incompatible RAM can make the BIOS go nuts.
I personally observed strange issues with my Gigabyte FM2 board caused by the LLC Auto settings ,right from the start.
Otherwise i can up my 5600K to 4,2Ghz/900Mhz/NB 2000Mhz easily.
Another observation would be the Windows 8 usage , it can cause problems with the 5800K due to the way it does power management in some scenarios.
A little off , what scores are you getting in Basic 3DMark 11 with that APU and the Nvidia video card ?!
Is the CPU side of the APU feeding enough the 3-rd party GPU ?!