Wifi Extender half duplex problem

Single and dual band extenders by their very nature drop throughput 50% off of what their receive from the router. That's what they receive. So if they're a bit aways from the router and there's interference, if they're only getting 70% of the speed, its half of that. That happens because they use the same chip to talk between the router and extender and then extender and device. And it can't do both at once. 

Fastlane attempted to help a little with this. It can help reduce latency but it doesn't help much with speed and here's why. 

2.4ghz is slow and sensitive to interference. If its set at the dedicated connection between router---extender, it bottlenecks the speed between those 2 devices. If the 5ghz is the backhaul, then your connection between extender and devices is slow.  The main purpose of it was to reduce latency and to help at the peripheral . 

With that said, you can get tri-band extenders that dedicate a backhaul 5ghz between router and extender. They don't suffer the same throughput loss. But they're more expensive. 

And I never recommend using more than 1 extender. If you're needing more than 1, its recommended to switch to a mesh system (and a triband at that). Then there's something controlling the system (the router). They'll be more stable and faster.