I don’t think I understand this well, but I have run some tests. From what I know, with most ‘spohisticated’ instruments (e.g. Halion, Kontakt, maybe EW, VSL not sure), they load a ‘header’ in RAM. This is the first part of the sample which can be played, even whilst the PC is rummaging around finding the rest of it. The size of these headers is variable in Kontakt, and the ‘correct size’ depends on the disk’s speed amongst other things.
Every note in a deeply sampled instrument, is sampled numerous times, so, for an eighty eight note instrument with say 10 sample layers, this means 880 sample headers loaded. An orchestra can contain say 50 - 100 instruments, multiplying the headers by 100 to 880,000 24 bit headers. If you load other stuff it can be much much more. This is why the amount of RAM in orchestral templates quickly maxes. Of course you have to add around 4 gig,m for OP, Cubase, Instances etc.
Most of these samples you DON’T need. Your probably working on only a track or two at a time, for all the other tracks, the only samples you need are the ones that get triggered by the previously recorded MIDI track.
Once a track is estabilished a good sample player will offer a purge facility. In some cases its OK to purge a whole rack instrument so called ‘global’ purge. Mysteriously global purge has gone missing as a button in Kotakt 5, it may be auto, but I don’t know. Setting up a template in purge mode for all instruments is a good thing to do - you then just activate the tracks you really want.
What about Freezing tracks?
Freezing an instrument “renders the instrument [& track?] into an audio file and unloads it” (Operation Manual).
There is also an option in prefs/VST?Plugins, which lets you “suspend VST3 (note not VST2) plugins when no audio signals are received” .
Instrument tracks can be frozen, but MIDI tracks cannot (there is no option in Track control settings for MIDI tracks).
When you freeze an instrument track you are apparently “freezing it’s channel” (Operation manual pg 100). But I thought that an instrument track is multi-track, these days? The manual does not explain.
When you want to freeze a multi-track rack instrument, then had for the rack and hit on the snowflake icon. Here you can freeze the instrument only or the instrument and it’s channels. At this stage I am not sure what happens if you only freeze the instrument. Both options leave the track playable, presumably by creating an Audio file, both lock the track from editing.
Disabling a track
I can’t find much in the Operation manual. There is only mention of disabling audio tracks. When a track is disabled, it is silent. It IS possible to disabl both instrument tracks and MIDI tracks. It does not seem to matter if the track is controlled by a Multi channel VST or an ordinary VST.
My aim is to create a lean maximally economic template with hundreds of tracks