QUOTE(blacktubi @ Sep 25 2017, 10:00 PM)
2.4Ghz is a very congested frequency. Many wireless devices like dect phones run on 2.4Ghz. Even your microwave oven is 2.4Ghz as well.
The interference issue is very apparent at condominiums where there are a lot of routers in close proximity.
Theoretical wise, it can reach 100Mbps but the maximum throughput is limited by the severe interference.
40Mhz on 2.4Ghz is going to make interference worst and not better. Not many devices in the market support Wireless N 300 as well.

Ya. I agree with that. However, only laptop are capable of getting full speed.
Most laptops now have 2X2 Antenna Wireless N. All smartphone limit to 72 Mbps only.
Now new technology is getting better today. In the future, all devices will have 5GHz.
Satisfied after changing new router from ZTE ZXHN H298N.
Too bad, not all devices support 5GHz band.
Wait for the future to see it.