I have install the Premiere Pro CC 2015 and After Effect CC 2015 in Mac Pro 2013 with the display card AMD FirePro D500, I can set the GPU render in Premiere Pro, but cannot set it in the After Effect, only can use the CPU in the preview setting, how can I do?
AE only uses a few NVIDIA CUDA enabled cards for accelerating Ray-traced rendering. That feature never worked very well, disabled masks and effects on 3D layers, and NVIDIA changed the direction of their development of that technology so the Ray-traced rendering feature is no longer being developed by Adobe. They are working on other technology to use the GPU but it is not available yet. There is nothing you can do to enable GPU acceleration unless you have a compatible NVIDIA card.