The default configuration for Nessus in the 1.2.0 release of the NST will consume large amounts of RAM.

Please refer to the Nessus section in the NST FAQ for details on what configuration file needs to be editted to prevent this.

If you do not adjust your configuration, your NST probe will likely run out of memory after just a few Nessus scans and this would be a shame as Nessus is such a powerful tool.