Fortigate 60F - Slow internet up/down, new ISP with 1gb service.

[prash001]

Client site upgraded from a 30mbps/ down business service to 1gbps Comcast business service. Same firewall 60f in place. We had WAN2 configured for the old service, WAN1 configured for new service, once Comcast was ready we enabled the WAN1 and disabled WAN2. Firewall rules/policies are 100% mirrored.

We have a physical server with 1gbps NIC enabled, when we try to do speed tests we get roughly 120mbps down and 40ish up. We go out to the office where the users laptop is connected through a VOIP device and run speed test and get over 300mbps down. The server is connected directly through an HPe switch which is connected to LAN1 (hardware switch) on the firewall at 1gbps. The workstation passes through the VOIP device, to a wall plate, to a patch panel, and to the same switch the server is on.

At this time, all connections are set at Auto and show 1gbps full. We tried to disable UTM and actually got slightly worse speeds when testing the server getting barely 100mbps down. I have triple checked to see if there is any other bandwidth throttling happening and I cannot find anything.

Comcast tech was able to pull 950+ downloads from the business modem, which was confirmed from the client, so we are pretty confident something is going on with the firewall, but can't pinpoint it.

WAN1 is set as manual, no PPPoE, no estimated bandwidth configured, no traffic shaping enabled, minimal admin access but using FMG

Anything else I should check?

[Yurisk]

I'd try to run iperf from the Fortigate itself, to exclude the LAN altogether, also, if still active - to run iperf on both, old, and new lines. If getting Ok speed on old line and bad iperf on new one - unlikely FGT issue, if getting OK iperf on just new line, unlikely FGT, likely LAN issue. 

For how to run iperf just Google "Fortigate iperf", you will need external server as peer for iperf though .