client memory usage high

When running a ddboost oracle backup the rhel client memory and swap memory are being almost completely consumed. Any way to control this? Secondary issue is that the rman backups are much slower than they are when using networker, to the point where they will not meet our maintenance window times. Writing to the same data domain using ddboost. We are testing ppdm to replace our currently networker backup and never saw this issue in networker.