I have a client that uses the ASA 5520 as both a firewall and VPN termination device.  Day to day VPN usage is 30-50 users and the memory (512 MB) is typically at 50% while the CPU is mostly under 30%.  I've suggested the RAM be upgrade to 1GB.

The client would like to add a large block of VPN users which could see 250-300 concurrent users.  What kind of a system resource hit should the expect with this level of load?

ASA verion is 8.2(2).

Thanks.