Some tips that @Ali_B shared on the Facebook group:
A couple of things I have done on very long signal chains. Firstly, using Amplitube 4 instead of Amplitube 5. For pedals there is no improvement to the sound in AT5. Way lower cpu.
Secondly setting the i/o of each block to mono. It doesn’t halve cpu use but it is a significant percentage if you’re on the edge.
TBH on sensible chains where each rackspace is targeted to specific sound (4-5 FX blocks) these are both unnecessary for me even on a 10 year old MacBook Pro using a 128 buffer size.
Running Diva at ‘great’ rather than ‘divine’ resolution and ‘multicore’ helps too, but I’m only using 3-4 note polyphony and my preferred patches don’t seem to tax the cpu.