Prime 95 stresses random access memory (optional) and CPU, GPU is not involved. The same goes for rendering unless you use GPU accelerated Vray or similar.
On the other hand, even idling in the editor already utilises some GPU power, adding to the overall temperature - if you now combine it with a tiny form factor and average cooling solutions used in most laptops, you will end up with a potent radiator, perfect for chilly winter evenings.
Anything above 90 degrees sounds a bit scary. Monitoring what your GPU is doing during those peaks will most likely solve the mystery.
Make sure the vents are not obstructed, point a fan at your laptop or invest in an additional cooling solution - USB powered cooling pads can work like a charm and you can get a half-decent one for $25.