Enabling IDS or IPS will affect the maximum throughput on inter-VLAN and egress traffic.
USG: 85 Mbps*
USG-Pro: 250 Mbps*
USG-XG: 1 Gbps*
Enabling Smart Queues or DPI on top of IPS/IDS will also incur a further throughput penalty to maximum throughput.
UniFi Dream Machine throughput: 850 Mbps*
UniFi Dream Machine Pro: 3.5Gbps*