I'm having constant ping spikes on a ~10 seconds pattern when I ping the router using my W10 PC, but only when connected to the 2.4GHz network. Sometimes the ping is high like +1000ms, sometimes a timeout is given.

 

Router ping:

 

2.4GHz in my region:

 

This makes online playing and remote desktop working basically impossible. I've already tried a bunch of things like disabling one mesh feature on the router, updating the router firmware (it's the latest), resetting windows network settings, testing different driver versions of my Wifi adapter (including a chipset one) and so on.

 

So far the only workaround I've found is to force the connection to the 5GHz network. Strangely this behavior not occurs on my android phone. Did a new test today and the problem also occurs, but the ping spikes are way lower than on my PC:

 

 

My Wifi adapter is an Archer T4E, but the problem also occurs when testing with an Archer T3U. A brief test with a TL-WN823N (2.4GHz only) not showed this issue, Tested again and it also happens with the TL-WN823N:

 

so it could be something related to the 2.4GHz / 5GHz commutation. Disabled all networks in the router except the 2.4GHz and the problem persists.

 

EDIT----------------

 

Downgraded the firmware to the 221212 version but the issue persists. Tried to downgrade even further to the 220425 version, but the router didn't accept the file.

 

Did a ping test on a D-Link DIR-615 (2.4GHz only) standing next to the (turned off) Archer C6. No problems:

  

 

So the problem is not related to a possible traffic jam over the 2.4GHz.

 

I'm thinking that the Archer C6 V4 have a poor 2.4GHz signal/stability, as the DIR-615 performs perfectly fine standing next to it, and I've had a previous version of this Archer C6 router that didn't have this issue, sadly it died out of nowhere and I received this new version from the warranty.

 

EDIT 2--------------------------------

 

Connected to the 2.4GHz guest network, did a ping test and the problem was gone. Returned to the 2.4GHz default network and did the test again, the issue returned. Went back to the guest network, the issue was gone again. Returned to the default network and... the issue returned. Definitely it's a software issue related to the default 2.4GHz network of the router, so only a firmware update will fix this.

 

I'm not prone to wait the good will of TP-Link to (eventually) release a new firmware to fix this, so I'm thinking of sending it to RMA and demand a different router with similar specs in return.

 

EDIT 3--------------------------

 

Disabling smart connect function and giving unique names to the 2.4GHz and 5GHz networks seems to fix this problem. Giving the same name to each network (or turning on smart connect) makes the issue return. The guest network test above was made with the 5GHz guest disabled, so it makes sense to say that smart connect / same SSID causes the 2.4GHz network to become unstable.