If it used to run cool and now does not you are going to want to investigate the cleanliness and fans in your whole system.
Make sure they are all running and clean. Use some compressed air to blow out the video card.
Make sure to hold the fan blades still when you blow them.
It is not good for them to zip around with the air.
If that doesn't help and all looks fine, it could be that the thermal compound has dried out on the GPU.
This may or may not be a task you want to tackle.
You can search you tube and there are plenty of videos showing how to do this.
Before going that extreme and after you clean your system.
Try a manual fan curve adjustment.
You want to move those dots to have them run at 100 from 70 degrees on up.
If that helps you can experiment with back off that fan curve a bit if it is too loud.
The following page shows where those settings are.