As you can read in the Avalanche online Help on chapter “’Enabling Performance Mode on Appliances”:
Performance Mode on the appliance allows you to run at a higher performance level than in the default Functional Mode.
· Two 10 GbE test ports are bound together to achieve better performance. The first 10 GbE port in the set is enabled, and the other is disabled.
· The enabled 10 GbE test port can operate as a client or server.
· This mode provides a higher performance level than Functional Mode.
If for example you have 4x10GbE ports (ports 12 to 15), what this means in practice is that the Cores that were allocated to port 13 and 15, will be allocated to port 12 and 14. So port 12 and 14 will each have 6 cores available.
What you need to be careful to, is that more CPU power doesn't mean more Bandwidth. One 10GbE port will never be able to give more than 10GbE traffic in any case.
But what the CPU will offer is increased performance on generating Connections/sec, IPsec sessions or Open Connections out of a single port instead of two.
If you need to have 20GbE traffic, the only way to do that is to use 2x10GbE ports, in Functional or Performance mode.