[Eric Mackay]

I suggest you disable multiprocessing. CS5 does this automatically. Playing with the settings is likely to just either over or under schedule your processor. Test this by rendering out a scene with it on and with it off again. See what happens to your render time.

Also, check out this script. It is free and will allow you to render in the background. This will make AE use only spare cpu cycles, leaving you to work in FCP with ease. It will of course slow your renders a bit depending on what you are doing.

https://aescripts.com/bg-renderer/

Also, do you have your cache enabled? Enable it and set the size to be equal to how much ram you have. This will speed up your renders.

As for OpenGl… nearly everyone turns this option off for rendering because it degrades video quality. But if you like using it in your preview window go for it, you might see some speed increases. I turn it off because it causes stability problems for me.