You said: " I got temperatures in mid 60Cs with a high of 71C with (stock cooler) ". May I ask you a few questions if you don't mind?
1- What is the stress test type you have done to get that temp (FPU stress or CPU stress)? And with what program? Test duration?
2- What is your Vcore and CPU frequency during that stress test?
3- What is your room temperature?
4- Is the air flow inside the case good or not?
5- Your motherboard model?
Note: I get mid 70Cs @4.2Ghz during the normal stress test only using XTU, AIDA64 Extreme, @4.4Ghz I get 79c except when I use torturing test using prime95 28.5, AIDA64 Extreme (FPU test) I get ~97c but as I understand those tests (FPU stress test for example) are not a real-life scenario, for the normal usage in the worst case when the CPU is fully utilized I get 81c @4.4Ghz using stock, room temp 26c.