I guess is ok. I'm playing with GTA V and reached a maximum of 91º, but usually 85º or so. The GPU about 75º. Somewhere I've read that less than 100º is ok (I have the 4720HQ by the way).
80 is fine. 85 starts pushing it. I also had peaks of around 91. Less than 100 is "OK" because that's thermal junction - aka the point where your CPU will kill itself to prevent...well...killing itself.