Here are a few tips to squeeze more out of your system. Forgive me if I'm patronising you with any of these.
Do you know what the buffer size settings are?
Lower settings give better latency but work the machine harder.
Higher settings give higher latency, which doesn't matter when you're mixing, and go easy on system resources.
Also take a look at the settings for cpu % use and no. of processors in use in Setup>Playback engine.
It's better to set no. of processors to one less than you have. Eg, 3 out of 4.
Set the percentage somewhere shy of the top....85% maybe?
Seems like it wouldn't help, but it does.
There are a few other things you can do to keep things smooth. Do you keep your plugin instances low?
Ie. Instead of having four reverb
plugins, just have one on an aux track and send all your stuff to it.
Is your
session on an external drive? It should be. Most laptops have 5400RPM drives which aren't ideal.
Are you using elastic audio? Turn it off and commit to your changes once you're done. That saves massive resources!
I'm sure there are more tips but maybe these ones will help.