A 95w fm2+ apu or cpu is unlikely to get above 50c with a gammaxx 400 , even the gammaxx 300 should keep it mid 50's.
They're both quick fit coolers & dont require any access to the back of the board.
You screw the amd mounts that come with the cooler to the heatsink & clip it to the board plastic bracket exactly the same as you do with the stock cooler.
The gammaxx 400 is more.or less on par with the 212 but the fan is quieter.