I’m running LO 188.8.131.52 on Ubuntu Linux 18.04. As with previous versions, the process soffice.bin frequently shows a persistent 100% CPU load, heating up the CPU and draining my laptop battery.
I usually have several documents open in Writer and Calc at the same time, on of which is rather large (185+ pages with about two dozen images). That might be related to the problem, however if LO is starved for memory I’d expect that to take the form of slowed response, increased swapping and the like, not a maxed out CPU load.
Old (and now apparently obsolete) forum posts suggest tweaking memory settings, which as far as I understand no longer applies. I can’t find any other “tuning” options in LO, unless there’s something under ‘advanced’ that I’m unaware of.