It looks fairly normal to me.
I get about the same results on my FX-6300 on a Hyper 212+ with two fans at 4.8Ghz and a slightly higher Vcore at 1.568v.
It is in a Asrock 990FX Extreme 4 motherboard with 8GB of ram at 2133Mhz.
I have had it to 5.0 and post but no boot at 5.1Ghz.
The cooler I have is not enough to keep it at 5.0 stable or to push for 5.1Ghz as the temps shoot to 70c and above rather quickly on a Prime95 load but will pass a Wprime test.
Talking really high temps here but I didn't kill it !!!
It is marginal for 4.8Ghz even but I don't game or run heavy loads on it until I get a better cooling system.
But it is fine for everyday use.
4.8Ghz seems to be about the sweet spot for these chips.
I also have a FX-6100 at 4.75Ghz that was at 4.95 Ghz on a Cosair H100 and it hovers right at 66c under a full prime95 load 100% 24/7 stable at a slightly higher voltage at 1.632v or so.
You can feel the heat being pulled off by the H100 and I think that is about the limit for that cooler.
It can handle more heat but I don't think that the pump is flowing enough for anything higher.
The radiator temps are only about 35c as measured.
At 4.95Ghz or 5.0Ghz the FX-6100 temps can get as high as 68c but never went above it and typically stayed at no more than 66c to 67c as well.
Then after about 3 months it started dropping 2 cores so I back it down to 4.75Ghz and is completely stable now.
This machine will never see a game but it will do some occasional video encoding.
It seems that once you get these chips hot it takes a little more voltage to keep them stable then what it took when they were new out of the box.
Both machines are running fine and stable the way they are.
To get past 4.8Ghz you need some serious cooling to take the voltage above this.
FWIW
jer