My wifi was not performing well and I tried messing with many settings. The ones that finally helped were the RTS and Fragmentation threshold. The fields in openwrt were empty, and in Verizon FioS’s quantumm modem they were 2346 for the fragmentation threshold and 2347 for the RTS threshold.
I will try to improve this some more, but I went from 50Mbit/s to about 200Mbits. :-)