Pages 167-168 of the vmPRO user guide covers Enable HotAdd Transport and Skip reading of page file and swap partitions during backup features. You can enable both by selecting these options in the advanced settings. These options will increase performance.
Also enabling the CBT option will increase performance seeing a CBT backup does not have to move as much data from the VM when preforming a backup. If export is only enabled on the VM then you are running a full backup every time. If export and CBT are enabled then you are running differential backups which save on time and disk space.