The Gigabyte Ga-78lmt-s2 only has 3+1 power phases - very poor for volatge ocntrol in general and especially the cpu. So you can't overclock on it.
It will only handle a 95W cpu and so you can't put an FX8350 on it. It doesn't have heatsinks on the vrm - so again, poor voltage control and overheating.
For a R9 290 in your pc, you'd need 650W. For a R7 250 you'd need 380W.
For a R9 270x or GTX760, you'd need 500W.