Hey Shiny - no such thing as a foolish question!
The best way I can think of to explain it is to use the recording of an electric guitar as an example...
If you record an electric guitar using a mic'd guitar amp/cab to get your "tone" the DAW will record that as a "rendered" sound
If you then decide to add some compression, eq, other fx and some reverb within the DAW most software will do this non-destructively so that you can go back at any time and tweak the settings - eg change the reverb for a different type
To maintain this flexibility every time you play your project in your DAW these effects are applied in real time "on the fly" - ie your DAW will play back the rendered guitar recording (the sound recorded from the mic'd cab) and put the compression, eq and fx "on top" of this recording every time you play it back
It is this extra processing that can eat up CPU if you have lots of tracks and fx, soft synths etc. etc.
This is why you are not noticing much difference with just a couple of tracks
To save on CPU you can "render" the tracks so that they are permanently recorded with all of your FX applied - this is also known as "printing" your track or "bouncing" or "freezing" (which I will come back to later)
The rendered track is your original recorded track + all of the fx applied - so it results in a rendered file that does not need your DAW to apply the fx as they are already recorded onto the track - eg a WAV file
This has the advantage that your DAW now only needs to play the track back and does not need to do any "on the fly" fx - resulting in less CPU strain
The other advantage is that you can send your track as a WAV file to someone (eg a mastering engineer) that uses a different DAW or does not have the same fx (eg softsynths or hardware) since the fx are "recorded" onto the rendered track
The disadvantage is that your fx are permanently applied so you can't go back and tweak a setting
HOWEVER...
Most DAWs have a "freeze" function that allows you to let the DAW temporarily render your fx to save on CPU but you can easily "un-freeze" to make any tweaks to your fx settings, giving the best of both worlds
However, you may run in to problems sharing frozen tracks with others so it is always best to "render" them so that they are how you want them - you could always give 2 versions - one with your fx and one "clean" to allow the mastering engineer to have more options
If you have a half decent PC and audio interface - and work with a sensible number of tracks - it is unlikely you will need to render tracks until you have finished your project and are ready to share it with the world as a WAV or MP3
I hope this helps you understand how it all fits together
Boydie
