[Kong]

The fan kicking into overdrive means your cpu also kicked into overdrive. It means your computer is working harder to keep up. Nothing to worry about.

Your computer would take slightly more electricity and get hotter. The fan/heat sink should keep it cool enough. In the event that the fan was broken or clogged with too much dust then the cpu would over heat if that caused the computer to get dangerously too hot it would automatically shut off to protect itself. That is near worst case scenario. If it gets that bad then you want to look at ways of improving the cooling system.

Same would happen if you were using any other intensive program. What is intensive depends on your computer.