Ac66u and ac88 wireless speed issues

[Fenres]

I've started to experience issues with my wireless connection on my asus rt-ac66u, and the power button was broken, so I purchased the ac88. At first all seemed okay, but now I'm noticing the same issue. My wired speeds are around 200mbs while my wireless will be at about 70 on the first test, but after using the device for a few minutes the speed will scale down to about 1mbs. The same issue on any wireless device (tablet, phone, chromebook)

 

[deej78]

Could you try what I did? I disabled the Firewall on my ISP Modem and kept the Firewall on, on my ASUS N66Ru. I changed the ASUS to 20mhz, N only, on both 2.4 and 5ghz. This alone vastly improved range and ping over WiFi. I disabled the Firewall on the ASUS as well which improved things further but I put it back on because I am unsure of the consequences, using a PC with Anti Virus, iOS devices, Panasonic TV, Humax Box and a Shield TV.