Desktop (Gigabit Ethernet) → Secondary router running DD-WRT in 802.11n client mode → Main router, also running DD-WRT → Cable modem:
![](https://www.speedtest.net/result/9872834747.png)
![](http://www.dslreports.com/speedtest/65125234.png)
The download speed is slightly faster than the ISP-advertised 100 Mbps.
Any device connected to one of the secondary router's Ethernet ports gets slightly over Fast Ethernet (100BASE-TX) speeds to the main router according to iperf3. (That means it would saturate a Fast Ethernet link.)