Do I need the CUDA toolkit?

Ok I just discovered CUDA like right now, rushed off to try it, and got a render in a fourth of the time, so YAY! But my question is will having the CUDA toolkit make a difference in speed? On the blender sit it says to have the most advanced drivers, which I’m downloading atm and only mentions the toolkit for the MACs

On a Mac, yes, I found that I had to have CUDA.

Do I need it for Windows though? From the site it seems the CUDA toolkit is for developers.

can’t see why you would. when you have recent drivers installed, everything basically (usually) works out of the box with Nvidia on Windows.

Do you have a Mac?

i have an 8 core, with Nvidia quadro 4000 video card. Have the cc compiler, and tool kit installed, latest cuda drivers, and rendering on my CPU is still a lot faster then the gpu. My card has 256 cuda cores, I thought for sure cuda would be better then this. Any advice or hints on whether I have it working correctly?

i downloaded the BMW test blend. On cuda, takes about 4 min to render. On CPU takes a second or 2 over two min.

I’m no expert but try increasing the tile size for the cuda render (256 x 256), decrease light bounces and sampling (unless they’re already low obviously)