what is a normal gpu temp
Your laptop will not melt regardless of what you do with it... but it will slow the CPU/GPU down once the thermal limits have been exceeded (usually in the range of 90-110C). If you are worried about temps, simply prop the back of the laptop up with a book (or anything) to improve airflow. I wouldn't worry about a cooler unless you want to spend a lot of time with a 17 laptop on your lap/bed/couch (basically any non hard surface that will block the air vents). m.