I assumed Linux given the specs and that Chrome works at all.

Vote for firefox as you should be anyway. Another trick to try is an explicit tab unloader extension (for fine control of unloading) and/or the built in about:unloads .

All browsers seem to accumulate memory (and cpu usage) over time, sometimes you just have to shut it down and restart. (AKA have you tried turning it off and on again :) A daily (possibly shorter if needed) service to restart it can work.