The speed at which AE renders your compositions and plays them back is not related to that check box. That's only for how it handles the panels themselves. I mean, if you're using color management, it might make a bit of a difference, but not much. Also, that feature uses OpenGL, not CUDA.
The more important place to check that your GPU is working is in your project settings. Can it be set to use CUDA there or is it set to software only? It might not help you at all, but if you are using Fractal Noise, Lumetri, or any of the other effects that are GPU-accelerated (Gaussian Blur, Fast Box Blur, Sharpen, Brightness and Contrast, Find Edges, Glow, Hue/Saturation, Invert, and Tint), it'll help - perhaps by a lot!
Now, if you're using the obsolete, ray-traced renderer, you'll also want to check the ray-traced renderer's settings to make sure it's working there too.
You might consider updating your GPU driver (not the CUDA framework, but the actual GPU driver.)