yandoo wrote

I don't have that options. My problem was caused by too many networks around me and after a talk with my neighbors we agreed to set different channels. It still happens sometimes but it is way less frequent now

Don't worry! SPI firewall option is only visible in AP router mode or AP client router mode and no, I would not recommend to disable the firewall if using router mode to isolate a network ...

As for the drops in TX/RX rate: this is absolutely normal. It's switching between current offered speed and negotiated speed with clients. Take for example the SSID beacons: they are always sent at the lowest mandatory speed that is configured for a wireless network. Therefore, in b/g mode 1 Mbit/s is the lowest mandatory speed, so beacons are sent at 1 Mbit/s. If you use n mode only, beacons are sent at 6 Mbit/s, so those drops will go down to 6 Mbit/s. SInce beacons are sent 10 times a second, those drops occur 10 times a second.

If the quality of the link is bad, drops can go to 11, 54 or 72 Mbit/s even during normal data transfer, if link quality is good it goes back to 130 Mbit/s.

This is what you observe when TX/RX drops. If there are many other devices around interfering with your device, then those "drops" will increase.