A few weeks ago I swapped a FortiGate 100D firewall to a 90D firewall. The 100D was defective and needed to be replaced. Since the customer only has a 20 Mbps ISP connection, I thought that a FortiGate 90D would fit for the moment, since it has a firewall throughput of 3,5 Gbps, compared to the lower value of 2,5 Gbps from the 100D.
Indeed, it worked. However, the CPU usage increase was huge, almost related to the NGFW throughput. Here are some graphs: