Good time of the day!
I have 5 (five) NEXX 3020 routers which are based on the MT7620N chip. If I understood correctly then internally it has RT5390 (or not?). After reading different materials, I see that my router(s) has same Wi-Fi performance issues as Xiaomi Wi-Fi, some Asus (like RT-N14U) and other routers based on MT76** chips.
Also after reading different topics/manuals/posts, here and not only, I understood that LEDE/OpenWRT is using open-source MTK drivers which are not so good and that's why peoples around tries to patch it using proprietary MTK drivers.
Then I made a couple of tests with different LEDE/OpenWRT versions to measure Wi-Fi performance. All tests were made using iperf3 (10 minutes of testing). All other settings defaulted. Setup was also very simple:
Laptop(Centrino N2230) -> NEXX 3020 (via Wi-Fi) -> PC (via Ethernet, link = 1 Gbit).
Mini-router (NEXX 3020) was placed 10-30 cm from Laptop. It was without a plastic case. Like just uncovered board. Also, I put a radiator on the chip. Spent some time measuring temperature (to exclude throttling) and I can say that with radiator temperature never rose more than 40 C.
OpenWrt SNAPSHOT r7309-333e609703. Kernel Version 4.14.50
Average speed: 38.1 Mbit/sec
Min speed: 16.7 Mbit/sec
Max speed: 53.5 Mbit/sec
Desc.: as you see there were a lot of down pikes. Sometimes I see better results, like avg speed ~45-50 Mbit, but it must be even better. Usual stability test runs OK, but in case if I will connect my android device then AP disconnects it (yes, that device) right after few seconds.
Lede 17.01.4. Kernel 4.4.92
Average speed: 23.2 Mbit/sec
Min speed: 0 Mbit/sec
Max speed: 55.4 Mbit/sec
Desc.: Much more different pikes. Only here I saw packets drop, etc. Also only this F/W has error known as "Error - Dropping frame due to full tx queue 2". So, connection stability is very poor. The router can "die" at any time. First of all because of above error.
OpenWRT 15.05. Kernel 3.18.23
Average speed: 85.1 Mbit/sec
Min speed: 19.9 Mbit/sec
Max speed: 95.7 Mbit/sec
Desc.: Best connection stability. No issues with phones, no problems with usual connection stability tests. No bug "Error - Dropping frame due to full tx queue 2". Only sometimes I see connection speed drops.
So, in general, OpenWRT 15.05 is the best choice for my NEXX 3020 at this moment. But I would like to use latest available S/W and F/W. But I see a lot of raised topics, questions, and bugs related to Wi-Fi performance and stability with latest LEDE/OpenWRT (like starting from 2017).
Please tell me the current status of Wi-Fi issues related to MT7620. Are there any workarounds to stay with latest LEDE release? Are there any other options which I can tune up? Why do we see such huge stability & performance drop on latest releases?
P.S. sorry, I can put only one image in the post