If you want to send more data over each channel, go with the higher frequency of 80MHz. However, you get fewer channels with 80MHz as compared to the 12 non-overlapping 5MHz channels for 40MHz. For your home router, you can use 40MHz channel bandwidth on both 2.4GHz and 5GHz. However, there is less interference from other sources which means faster speeds on wireless networks where bandwidth matters most!