your GPU is 70C ?
hot spot is 75C or RAM?
88C for hot spot/RAM? ---- if this is a hot spot, you might benefit from a new TIM application - still that is not all that bad
I've seen my own cards hit much higher hot spots above GPU temps
What about lowering the OC on the GPU MHz? (how much is the OC?)
Are you case fans all clean & @ 100%? How many, size & push In or Out of case? (you need to get the CPU & GPU heat out of your case, before the GPU cooler recycles the heated air)
Are you using a custom GPU fan Curve? try setting a Curve based on Temp in C +20 = fan speed% 50C = 70% fan, 60C =80% fan
Any way to cool the room you in? fan, A/C .....