When the fios quantum is plugged in and I use the Verizon test I get gigabit or close enough. Taking the quantum out and putting unifi USG in I get 300/300 . In both instances, I'm hard-wired to the router.
I need to see if anyone fixed this issue. I am having the exact same problem at 2 different clients that upgraded to gig Verizon recently. When I use their G3100 wifi router thing and plug direct to it I get 950mb/s speeds. If I use my USG router I can only get around 200mb/s. Even if I use their router and connect it to my switch and try to get a speed test through the switch I get 300mb/s. So if I don't use their router I instantly drop to 1/4 the speed.
A tech came came out today and checked the fiber connections and the pole and all the stuff on his end. It was all good. He said you should be able to use any router you want as he has done it before. He had no idea what the issue could be and neither do I.
Any my help would be great I have a Ubiquiti USG a 24 port Ubiquito unifi switch and a cloud key with 3 unifi access points on the network. Not even worried about the wireless I would like to get it figured out hard wired first. I us every ubiquiti as I remote manage 30+ properties. I cannot be having this issue everywhere when they all upgrade as planned.
I think you'll get better traction if you pose you question as a new post rather than as a reply to a resolved post from ages ago.
I have a gigabit connection with an Asus AC 66W as the gateway router from the ONT via a long cat 6 cable. I get gigabit speeds fine. I even get gigabit Speeds on this laptop which is on the home CAT 7 internal network via a G1100 connected to the AC66W as a separate subnet.
This seems like a problem specifically to the USG. Could you double check with Ubiquiti what's their router's maximum NAT throughput? Also, have you enabled QoS or IPS features? Those would drag the speed down substantially as the CPU in USG is not the fastest.
We have customers using Cisco routers and even Linux routers built by themselves, they can pull the subscribed speeds just fine.
The USGs can do Gigabit speeds as long as Smart Queues and IPS/IDS are disabled and the L2 / Hardware Acceleration features are enabled. If any of those features are on, the USG 3P will cap off at 80-120Mbps, and the USG Pro 4 will cap off around 300-400Mbps. They have old MIPS processors and can't push traffic like their newer Dream Machines can, which do all of the routing in software on ARM processors.
The other thing to note is, if OP is running a speed test from the UniFi Controller, even if the USG itself is delivering 1Gbps of traffic, the speed test in the UniFi Controller runs off of the USG. The USG's CPU will bottleneck the speed test at the same speeds you'd expect to see if you didn't have hardware acceleration enabled.
A couple things do come to mind though.
1: Make sure the USG is fully updated. Firmware as far back as two years ago had issues with UDP traffic, and some of those issues also cascaded to TCP Traffic.
2: Turn off MSS Clamping. Not needed on FiOS as long as your network is already at an MTU of 1500 end to end.
3: Make sure Hardware Offload, Layer 2 Blocking Offload, and Offload Scheduler are all enabled.
4: If the USG is configured using Class A blocks on NAT, configure for Class B instead (old bug a while ago caused slow speeds if using Class As in some situations) and see if performance improves.
5: Log into the USG's CLI and run a `show interfaces ethernet detail` and look at each of your Interfaces. Make sure you do not see overrun, errors, or carrier collisions being reported for TX and RX on any interface.
I have a USG 3P on Gigabit DOCSIS and it handles the connection fine. A friend of mine has a Dream Machine Pro on FiOS and gets the full 940/940.