Amplitube is a resource hog. But were the best guitar amp emulation on that age. At least that is in my memories.
When playing with Amplitube, I insert that plug in a track that is sent to an aux. And I record that aux to a track. You can record hundreds (32 tracks on LE) of tracks using this trick.
My dual GHz can support 2 or 3 Amplitube RTAS at the same time at 128 of delay.
It is easy to work with low cpu resources if you BOUNCE a playback and make a new session importing all the markers and measures with just a stereo playback. Later, after all the guitar solos session recorded with the above method, you import the guitar tracks printed on the mix mother session.
Think on it as if a song needs 3 or 4 sub projects where you track the singer/bassist/guitarrist... Later the individual projects export tracks to mother project.
Even on the singer sessions, I print the vocal reverb on a track and I can later decide if I want more reverb or less.
Also, as guitarrist, I like to mix the original un-amplitubed guitar with the printed-distorted-amplitubed guitar. Later, on mix, I can decide how much distortion I want mixing both.
My favourite sound is 2-3 dif. amps + clean one.
[youtube]b-pkDd5epgk[/youtube]