No Gigabit speeds on Airport Extreme

When I plug that same cable into my Airport Extreme (version 7.7), I get speeds around 4MB/s.

First, are your measurements in Mega Bytes per second or Mega Bits per second? Your post indicates Mega Bytes. I just want to be sure. Internet data transfer rates / bandwidth are typically indicated in Mega Bits ... so a Gigabit service = 1000 Mbps, not 1000 MBps.

Based on your "840MB/s" statement, I will assume that you were getting around 840 Mbps of data throughput. This would be not be unreasonable for Gigabit Internet service.

If you meant 400 Mbps at the AirPort Extreme, then, this would not be out of range for what the Extreme (in its default router mode) can deliver. You can get an idea on how a number of routers perform at this SmallNetBuilder site. All routers, with NAT enabled will reduce the available bandwidth. That's how the OSI model works.

ISPs, typically sell / advertise upload / download speeds for bandwidth, not data throughput. There is a significant difference. Also, most consumer-grade Internet service does not guarantee those bandwidth values. You would have to step-up to business-grade service for that.

Router manufacturer's also sell / advertise the potential bandwidth as their router's speed measure. Most of the time, to achieve those speeds that router would have to be configured as a bridge (routing disabled).

As always, caveat emptor when reviewing ISP/manufacturers' claims.

Thanks, I just wanted to be sure. 4 Mbps is definitely horrendous results! Let's see what we can do to help.

Did you run the web-based speed test with your Mac mini connected to the base station by Ethernet or by wireless? Regardless, have you had an opportunity to use other similar speed tests, like Speedtest.net and got similar results?

Since all 802.11n or 802.11ac Extreme base stations can run the 7.7.7 firmware, which exact model is yours? Also, what is the make & model of your ISP-provided modem?

In the mean time, If you haven't already, please give the following two things a try:

1. Try each of the Extreme's LAN (opposing arrows) ports, using the same cable each time, to see if that makes any difference.
2. Try another known-good Ethernet cable. It doesn't matter if it is CAT-5e, 6, or 7.

Ok, the Hitron CODA is not a simple modem, but a combination modem & wireless router.

Since you basically have two routers in series, the downstream router (your Extreme in this case) should be reconfigured as a bridge. Is it?

Just disabling wireless on the Hitron would not disable its routing (NAT & DHCP) functions.

Configuring the AirPort as a bridge would disable port forwarding, but not its wireless radios. The Hitron would still have NAT enabled and where port forwarding would need to be configured.

The bottom line is only one router should be enabled for routing, otherwise you will have a "double NAT" condition which would be inefficient and potentially problematic.