I am trying to render in After Effects, and I find that it is going extremely slow. At the start of each frame, my computers's CPU and GPU usage spikes to normal, then immediately falls to near 0% for like 20 seconds. It does this every frame, making the rendering process take much longer than it need to. I'm only rendering around 350 frames in a .png format with only keylight, advanced spill supressor, and a few color key effects. This makes no sense to me. I am running AE off an SSD, however my files are running off a HDD.
And what footage? What output format? Is multiframe rendering active? What are the keylight settings? What the other effects? Overall this sounds not out of the ordinary, but I have a hunch that you may have issues with hardware acceleration where the program optimistically loads a frame, tries a bunch of times with GPU acceleration and multiframe rendering and then ultimately falling back to single-core CPU processing. This could be caused by a single overcranked setting in Keylight for instance, which is quite a resource hog to begin with. So for what it's worth, you may not be able to fix or improve this completely. There just may be some potential for tiny optimizations and at least avoiding this time-wasting back and forth between CPU and GPU modes.
Thanks for getting back to me, and sorry for the late reply. My footage is an image sequence from a Canon camera (res is 4480x6720). The resolution is high, but my computer is substainially more powerful than my work's, and I've never ran into problems. Mulit-frame rendering is active. Output format is .png, rgba, million of colors+, no compression.
I have 4 color key effects before my keylight. After that I have an advanced spill suppressor.