Acceptable to who? To me? To me? Let's see. The maximum operating temp is 100C. That is aka 212F or the boiling point of water at sea level. Anything above 85F would be a huge concern for me. This would only apply with laptops. If my desktop's 970 exceeded 70, I would be concerned. Laptops generally run hotter.
When is the last time you used canned air to clean out your exhaust fan and other parts of your laptop?
What is the average ambient temperature when you are gaming?
Do you use a laptop pad like
https/www.amazon.com/HAVIT-HV-F2056-Laptop-Cooler-Cooling/dp/B00NNMB3KS/ref=sr_1_2?s=pc&ie=UTF8&qid=1465659277&sr=1-2&keywords=15.6+laptop+cooler ?
86C? Acceptable? Nope. Some people routinely game with their GPU at that temp., on both laptops and PCs. Do I think they're right in doing so? Nope. But we all have opinions.