I've spent about a day and a half now going through the list of things that would hopefully fix this problem, yet it persists: my after effects files render extremely slowly. I can confirm that this isn't for a lack of computer processing power; I viewed the PC's resource allocation in Task Manager and the amount of CPU being used was well under 80%.
I'm sorry for not yet providing any additional information, I just don't know which pieces of information to share first.
which pieces of information to share
Exact system specs, version of AE, comp settings, render settings, effects and stuff used and so on. Otherwise just saying that AE renders slow is as useless as hair on your back...
What are you trying to render and preview? No details means there are too many potential problems to list. The most obvious problem would be that you are trying to use the obsolete and never worked like it should have Ray-traced rendering option. The second most obvious problem is that you are working with an incredibly large frame size or incredibly large assets for video. Another common problem is that you have fouled up the AE preferences and have not left any resources available for other apps. Reset your preferences, try a project using standard presets like HD TV 1920 X 1080 29.97, and let us know if this helps.