Hi this is a common issue for the asus X540U due to the laptop's "small heatsink" for the gpu and processor (yes they are only small chunks of metal with no heatpipe. i suggest cleaning it out and replacing the thermal paste will help too. this will help only a little. The most stable way to fix this problem is to make a custom heatsink for this. The current thermal design of this laptop is not sufficient for the components it comes with. (unless you are using this with an i3 or lower processor.)