Depending on your Daw, there's a lot of options.

If you're in Logic you could make a new Alternative where you bounce all the tracks in place, and if you're in Ableton you could save a new .als file and use the older version as a backup!

Regardless of DAW, you could always duplicate the tracks, mute and bypass the original (and hide it, if your DAW allows), then bounce the duplicate to audio!

You could also create a new audio track that accepts audio input into whatever track you want to bounce, then record a full pass of what you're bouncing onto that new audio track!

As stated above.
If during the bounce phase your machine overloads then in Logic you can Freeze certain processor hungry tracks which will allow you to export all of the stems. You can then bring those stems into a new arrangement and mix without the draw on resources of your vst or au synths etc.

best reccomendation is to invest in a strong computer, you wont regret it in the long term cause of workflow and speed
other than that, to save CPU is to bounce audio by freezing and use less cpu hungry vsts like sylenth, sylenth doesnt use much CPU and use stock plugins i think

This.