Delay before changes take effect makes it hard to apply effects in real time

[Togethernet]

I have about 8 audio tracks and am mixing them down - I want to adjust reverb or other effects while playing back but when I change a setting there is a delay of about 5 seconds before it takes effect, why is this?

I'm using a 3.4GHz Intel core i5 iMac with 8Gb RAM and plenty of spare disk space.

[SteveG_AudioMasters_]

It depends which reverb you use. If you use Full Reverb, for instance, it has to re-calculate everything whenever you change a parameter, and this takes a while, even on a really fast system. Some of the others are much faster to update.

[Togethernet]

OK, so just having full reverb in the mix stops me making any real time changes. So I can disable full reverb while working on other effects but what if I want to automate full reverb? I need to set different levels starting with a little and adding more later, and I don't see a way to add envelopes for this an I can't do it in real time.