Per the datasheet-
Virtual devices provide a means for creating resource segmentation and isolation, allowing the Cisco ACE appliance to act as if were several individual virtual appliances within a single physical appliance. Virtual devices enable organizations to provide defined levels of service to up to 20 business organizations, applications, or customers and partners from a single Cisco ACE appliance.
Complete separation of the following:
• Configuration files
• Management interfaces
• Application rule sets
Customized, guaranteed resources per application for the following:
• Throughput
• Connections per second
Capability to limit and manage the allocation of the following Cisco ACE resources:
• ACL memory
• Buffers for syslog messages and TCP out-of-order (OOO) segments
• Concurrent connections (traffic through the Cisco ACE)
• Management connections (traffic to the Cisco ACE)
• Proxy connections
• Setting of resource limit as a rate (number per second)
• Regexp memory
• SSL connections
• Sticky entries
• Static or dynamic network address translations (xlates)
You don't allocate CPU/memory, but you can set limits on resources listed above which generally map back to CPU/memory utilization. The CPU/memory are "global".
Hope that helps.
