Hello, I'm barely getting 280Mbps download speed through WIFI and what I'm paying for is 500Mbps. I've tried different places in the house, but still the same. (It's working great with an Ethernet cab

After the last firmware update, my decos lan ports limited the speee to 100Mbps (M4 has gigabit ports). However my wireless speed is 300Mbps, the same as the provided by my ISP. My network topology is