So, unfortunately those are both lower quality, but the motherboard is definately the bigger problem.
http://www.tomshardware.com/forum/id-2384030/motherboard-tier-list-am3-chipsets.html
The Smart series power supplies are terrible examples of what a name brand power supply should be, but at 750w, which is probably only consistently about 500w on that unit, it should still be ok so long as nothing is wrong with the power supply itself, which there might be. Wouldn't be surprising since that unit uses rather cheap caps.
How old is that power supply as far as how long has it been in service?
The motherboard is a different story. That board should never have been used with any FX6 or FX8 cpu. It has very poor power phase, with low end VRMs and power delivery. Use of an FX6 or 8 core CPU have likely caused serious thermal fatigue and you are probably seeing capacitor or voltage regulator failure, or electrical fatigue. If you wish to continue using that platform I'd highly recommend a new or at least new to use, higher quality motherboard. Better by far would be to just upgrade the whole platform but that would be a more costly investment, in the neighborhood of about 240 bucks for an entry level Ryzen or i3 upgrade for CPU, motherboard and memory.
These are the boards that I'd recommend as being suitable for use with that FX 6 core CPU. The closer to the top of the list, the better. All of them are members of either the 990fx, 990x or 970 chipsets. This is important because there are other, incompatible chipsets that use the same naming/series schemes as many of these models, but they will not be compatible as they will be different chipsets.
GA-990FXA-UD7
Extreme6
Extreme9
Fatal1ty 990FX Professional
Crosshair V Formula-Z
Sabertooth 990FX R2.0
GA-99FXA-UD5
MSI GD80V2
M5A99FX PRO R2.0
GA-99FXA-UD3
MSI GD65V2
990FX Killer
Extreme4
M5A99X EVO (R2.0 as well)
GA-990XA-UD3
990XA-GD55
GA-970A-UD3P
M5A97 or EVO or PRO (R.2 as well)
GA-970A-UD3
970 GAMING
970A SLI Krait (USB 3.1 supported)
Extreme3
970 Extreme3
M5A97 LE R2.0
970 Pro3 (R2.0 as well)
GA-970A-DS3P
GA-970A-DS3
GA-970A-D3P