How to fix high ping on wifi?

Question

Computer networks

Guys help me out, I've already broken my whole head.
Problem essence:
There is a local area network, on it 60 machines. We put separately Wi-Fi and gave access.
As a result, the work of Wi-Fi is very strange, sometimes pings are 1-10 ms, sometimes 2500-4500 ms, or do not respond at all. And the timing is different each time.
What they sinned about:
1) The router was in conjunction with the MFP, disconnected the MFP, the pings became normal, but not for long.
2) We thought that the router was bent ( ASUS RT-N66U ), bought Zyxel Keenetic GIGA II , but nothing has changed.
3) Contacted Zyxel support, they advised programs:
InSSIDer - WirelessNetView - Free Wi-Fi Scanner
Like, scan the network and select the desired channel. They did it, nothing has changed, just like last time, it helped for a while. 4) We thought the firmware would go out, put it on ASUS Merlin Build, again the same thing. 5) We thought torrents, but there is no way to trace it. 6) Perhaps someone is downloading something from the phone, but they tried to change the password and sit at this point from 1 account, there were no changes with pings, they also jumped. In general, I'm waiting for advice and examples of solutions that can be tested, right now, while it's ASUS RT-N66U (Firmware version: 3.0.0.4.376.45_0 (Merlin Build)) . Willing to provide additional information if needed. I can post the logs if you tell me where.

Answer 1

Wi-Fi on the same ip subnet as all computers?

Answer 2

If pings are falling on one channel, then the air is clogged, look with a scanner who is shitting.

Answer 3

It's time to stop using wifi in applications that are critical to ping. Alas, you will not achieve the best wireless communication (unless, of course, you move to a village where the nearest router is several kilometers away)

Answer 4

the processor of any router simply will not pull out 60 computers, put a pfsense or kereo gateway