Most of the default settings pertaining to memory utilization in SQL Backup are already running at their maximum values. The only variable that affects memory utilization is the number of threads used to perform the backup.
With a larger thread count, SQL Server needs to allocate more memory to store the backup data before passing it to SQL Backup. However, it also imposes a higher requirement on your disks. If your current bottleneck is your disks, and is usually the case, increasing the thread count wouldn't help in making your backups faster.
In the SQL Backup help file, there is a topic titled 'Optimizing backup speed', which provides some hints on how to identify the bottleneck and to determine the optimum number of backup threads to use.
SQL Backup Consultant Developer
Associate, Yohz SoftwareBeyond compression
- SQL Backup goodies under the hood, updated for version 8