How you can bake textures faster in Blender's Cycles render

I needed to make a realistic tree log texture in Blender and found this tutorial: Blender Tutorial: Photorealistic Material. It turned out I needed to use Blender's Cycles render for the first time in my life. This render is node based and it makes it more complicated to export the material to a game engine like Unity. To export the material, you have to bake the diffuse texture, which is easily done if you follow for example this tutorial: How to make a bake texture in cycles. The result is this:

The problem was that baking the texture was really slow. When I googled the problem, most answers suggested that to make it faster you should make the texture you want to bake to smaller, such as 512 and not the 2048 which is what I wanted. But the one with the answer was no-one else than our dear friend Blender Guru and his video: 18 Ways to Speed Up Blender Cycles Rendering. The one "way" that improved baking was "#3 Use GPU." Apparently, most likely because not everyone has a GPU compatible with Blender, Blender is not using the GPU by default when generating images but the CPU which is slower. To tell Blender to use the GPU, you click File → User Preferences → System. And then at bottom left, you should select CUDA:

But that's not it! You also have to set the render to GPU Compute (CPU is default) in the panel to the right:

The results:

• GPU: 2 minutes 33 seconds
• CPU: 9 minutes 42 seconds