I'm a compositor who works with After Effects and am in the market for a new computer. I am trying to decide between an iMac (3.5 GHz quad-core i7, 8 to 32 GB RAM, 3 TB Fusion Drive, NVIDIA GTX 780M 4GB GDDR5) and a Mac Pro (3.7 GHz quad-core, 12 to 64 GB RAM, 256GB to 1 TB flash storage, and Dual AMD Firepro D300 GPUs with 2 GB of GDDR5 VRAM each/D500-3GB/D700 6GB). I was hoping for some advice on whether the Mac Pro is worth the extra investment for After Effects - will the software benefit from the additional power, or will an iMac be sufficient?
After Effects is a CPU and Memory dependant program. The MacPro will be faster, more expandable, more capable in every way in the long run. Take any money you can save on the GPU's and spend it on ram, buy some thunderbolt external storage, an array if you can afford it. The external storage is a good idea for any system. The iMac will have a GPU that is capable or Ray-traced rendering but this is a very small advantage for a very limited type of project that will be of little advantage in the grand scheme of things.