Optimize time when creating archive

Currently I am using the following command to create an archive with files older than 7 days: find /var/tunningLog/ -type f -mtime +7 -print0 | tar -czf "/var/tunningLog/$(date '+%Y-%m-%d').tar.gz" --null -T - && echo "OK" || echo "NOK" But it is taking to long (currently /var/tunningLog/ has 49G). Is there any way to speed up the process or to improve the command? Thx