I should also mention it is the latest Mac pro, eight core.
You don't have an NVIDIA card so you cannot use CUDA. Do Not Install CUDA drivers.
CUDA acceleration was only applied to Ray-traced rendering. This is no longer being developed and it never worked well. Don't worry about it. If you have CC 2017 then you can use the C4D Rendering option. It works a lot better and no additional drivers or monkey business is required.
Thanks Rick. Too late I have already downloaded the drivers. Ouch!! So how do I get rid of the drivers and will they alter anything.
It was very confusing. Where is the C4D rendering option?
Downloading is ok, installing is not. If CUDA shows up in your System Preferences then you have to jump through some hoops to uninstall. I don't have time to look up the procedure for you but there are several threads in this forum with links to the procedure.
If you have CC 2017 then just open the advanced tab in Composition presets or click on the Classic label in the comp panel and it will take you there. If you are running an earlier version of AE you'll have to upgrade to use the C4D rendering engine. ONLY use the other rendering options if you can't achieve the effects you want to achieve in any other way. You loose things like blend modes, effects and a bunch of other functionality when you use the advanced rendering options. Make sure you read the warnings
Edit: found the uninstall instructions: Installation Guide Mac OS X :: CUDA Toolkit Documentation