I also read that the FX series shouldn't have too much trouble getting up to 4.8GHz on air, provided you have a good air cooler and decent ambient temps. I wouldn't be too worried pushing temps to 65 (recommended 62), but definitely keep below 70.
im on a watercooling loop with a dual 120rad top and a 120 rad in the front. both with NF-F12s but i still only get to 4.5GHz with acceptable temps. i tried 4.8GHz and got it stable with 1450mV but it got to 60°C while playing bf4 and up to 63°C with prime95 any voltage lower got errors in prime95.
nothing is wrong with my cooling and thermal paste is applied correctly so i must have one of the worst 8320s in existence ._.