I wasn't aware of tar's --blocking-factor parameter: -b, --blocking-factor=BLOCKS Set record size to BLOCKSx512 bytes. This actually reduces CPU load and backup creation times measurably. Figures for backing up 7GB on my home NAS: Setting Seconds Setting Minutes.Secods------------------------------default 1.18 512 1.071024 1.052048 1.08 The fastest setting (1024) is 11% faster than the slowest (default).