Netgate 4100 slower at 2.5gbe than 1gbe

[stephenw10]

What switch do you have on the LAN side currently? Is it linked at 2.5G to the pfSense LAN and 1G to the clients?

Try setting the LAN side link to 1G when the WAN at 2.5G so the bandwidth change is in pfSense not the switch.

If it's in the switch you pretty much need flowcontrol active to avoid buffer overruns.