Just moved onto Cityfibre/Zen, 2.5gbit synchronous, and the speeds from my PC varies from 1gbit to only as high as 1.3gbit down, but always 1.6gbit up.
I'm on a Firewalla Gold Pro, Cat7 cables, PC with an ASUS XG-C100C 10 Gbps NIC. Local LAN tests hit 2500/2500 Mbps, confirming the NIC, cables, and Firewalla LAN are solid. However, PC internet tests (Fast.com/Ookla desktop app) only reach as high as 1.3gbit down 1.6gbit up. On the Firewalla CLI tests sometimes get as high as ~2000 Mbps down, and I've done multiple iperf3 tests too on Firewalla via SSH, and they hover around 1.3/1.5gbit. Upload speed is always consistent at 1.6gbit though.
Any ideas?
Edit: Possibly figured it out thanks to gemini. When performing iperf3 on PC, using htop in firewalla console the CPU maxes out when performing the test, so the CPU is being fully utilized to route the traffic at ~1.2 Gbps, and it simply cannot process it any faster for a forwarded stream. Thought these routers were supposed to be high end for the consumer?