Tunnel mode performance

I've seen numerous references to AP's in tunnel mode being bound to the FortiGate CPU for performance, but most of those posts also talked about using a software switch.

In my case, I have a FAP-221E connected to a FSW which is connected to a FGT-60E n FortiLink.  There is no software switch in use anywhere on the FGT.   Is performance of the AP and WiFi clients still going to be bound by the FGT CPU or will the SoC on the FGT be used for processing traffic?