If anyone is stil tracking this thread, here are my latest thoughts.

EnditAll - thanks Mac. to be used with caution 'though, particularly the 'Kill programme' option.

For myself (home 'fun' use only - remember 'fun', the pros out there?) the only time system response times matter is in recording. For this, a really good, easily reversible solution may be as follows:
- disable Internet by disabling wi-fi adapter from dev. manager (as suggested by Mac above)
- once this is done, switch off AV & Firewall (surely these are the things that are eating system resources?)

As for having a whole new Internet DAW profile, the downside is you can't flip over to the net to find a lyric or a performance of a song etc. without changing profile.

But this brings me to another, oh so basic question.
Am I alone in finding that my system copes really well with a 'fully-built' midi file. (an x.mid or x.kar) whatever app I am using to read it, and irrespective of how many tracks/channels it has), but struggles somewhat with BIAB.

Is this because BIAB is, in a way, building the track as it goes along?