Yes Peter have one site running G1GC garbage first collector. Suggest perform some logging or monitoring to know altering GC has good or bad impact.
With G1GC allow for the heap to be much larger, it would be fair to say it is more memory persistent than PARALLELGC which is effective at keeping the heap evacuated. Example JVM args only, where this may work well with PARALLELGC:
this may suit better with G1GC given same load:
As always take a copy of your JVM.CONFIG before changes so you got a backup.
PS you might like these references