rubixgod :
I have this laptop. Also the CPU temperature is also hitting around 75-80C while playing games.
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/www.costco.com/HP-ENVY-15t-Slim-Quad-Laptop-%7c-Intel-Core-i7-%7c-4GB-Graphics-%7c-Backlit-Keyboard-%7c-1080p-%7c-Windows-7-Professional.product.100236556.html
Ah, I see. In that case, these are likely perfectly normal temps for this model. This laptop was designed with portability in mind, which often results in sacrificing cooling efficiency. Both of your temps you mentioned are perfectly safe, though.
If you want to lower your temps, you can look into raising the laptop about an inch, and/or looking into a good quality chill pad (such as the Notepal from CoolerMaster). The only other changes you can make involve you opening...