When you only game then R5 would do fine. R7 makes a bit more sense when you stream at the same time when gaming, and/or watching someone else stream when you're gaming (R7 is better at multitasking).
And yes, max what R7 can operate at, is 90C. While R5 can sustain up to 95C. Still, don't push CPU over 80C. Instead, get better CPU cooler/airflow inside your PC.