Not sure anyone would be able to translate that (Enhanded) into specific specs,
but from other screen shots - 8 Gig memory is total
'others' = how many?
Graph does show total processes but not specific processes per moodle.
Are the processes related to the 'other(s)' moodle the cause? You suspect the newest moodle installed but that could be a co-incidence, couldn't it?
Could be cron jobs got stuck in adhoc task which are qued up jobs that did not finish for some reason.
So in all sites ... check task list to see what might be failing.
Got command line? Got top? top is real time and watching it for a few minutes might show that mysqld is pegged at the top of the processes.
Ever 'tune' your DB server? - assuming DB server is on same server and not remote to where moodle(s) are located.
'SoS', Ken