The gigabit ethernet adapter integrated on your motherboard is more than enough. it's all about your ISP (Internet Services Provider) and the speed it provides you. There are some providers in some countries that offer Gigabit internet connections (1000Mb/s). For example, i have an 500Mb/s connection, that means around 60MB/s in download speed. It's by an optical fiber connected to a modem provided by my ISP and all i needed was my usual ethernet adapter intgrated on my motherboard in order to use this connection. I could've opted for the 1000Mb/s connection but i needed a more powerful CPU for that. The point is...it doesn't matter what adapter do you have if your internet connection speed provided by your ISP is low. So if you want super fast internet speed, you need a better internet service from an ISP, you don't need that 40G adapter.