AfterEffects CPU performance

Most of the time I have comp resolution set to Auto, Magnification Factor set to 50% or less and most effects turned off. I preview the motion, then increase the magnification factor to 100% and check a few critical frames with all of the effects in place. If the motion test, which is usually rendered in very little time is OK and critical frames look fine with all effects turned on then in effect I have done what traditional animators used to do with pencil tests. When the pencil test is OK the sketches are sent to Ink and Paint for polish. More than 90% of my comps are seven seconds or less and only one shot. Editing is done in Premiere Pro from rendered shots because that is the efficient way to produce anything longer than a few seconds in After Effects. Maybe 1 comp out of 10 ever gets a full rez ram preview with all effects turned on because I know how they are going to look and don't need to waste that time. Anybody can learn that skill.

If you are doing things with particle simulations and another time-intensive rendering projects it becomes even more critical that you figure out how to visualize the final result, send it off for rendering, then move on to the next comp. If you are cutting together several shots and your comps are 30 seconds or longer then you are using the wrong tool to do the editing, you are not going to be able to preview the entire film, your polish and fine-tuning of the edit is going to be complicated and time-consuming, and the end product isn't going to be as good as it would be if you used the right tools for the project.

Until AE can playback several streams of 4K material in real time without rendering previews and storing them in a cache somewhere AE is going to stay a tool specifically designed to create shots and short sequences and using it efficiently just requires an efficient workflow and the confidence that many visual effects pros get as they gain experience. It's exactly the same as working in a 3D app. You make sure that the polygons are moving the way you want them to move with real-time "pencil teste" then you texture, set up the render passes, add the lighting and the rest of the fine-tuning while checking a few critical frames, then send the shot off to the renderer and let it bake while you move on to the next shot in the sequence.

I hope this helps. The more experience you gain and the more efficiently you learn to use the tools the more productive you can be. I know a lot of folks that turn out eight to ten times as much footage in a day than a lot of folks working for the same production company and none of them rely on full resolution full frame rate full-length previews of a comp to figure out if it's time to render.