There has been lot of confusions regarding the frequency bands available in Wi-Fi routers that come with 2.4GHz and 5GHz dual band feature. If you've been shopping for router, you probably know that there are dual band routers, which are easily available in the market that allows you to connect on either frequency. But what actual difference does it make to choose either of them? And also there is not necessarily always a reason to use the 5GHz, sometimes it's better to use 2.4GHz.
First of all, yes! 5GHz is faster in general but not exactly a fertile reason as you might think that 5GHz is a higher frequency that means it can transmit data faster which is not exactly the case.
Why 5GHz Router is Faster?
The real reason 5GHz is faster is because the way it uses different channels and their arrangement with channels with respect to Wi-Fi frequency.. They are like small ranges of frequencies that are used to transmit data.
Obviously the router is not using exactly 5GHz for everything, there are different frequency ranges that are possibly to be used. In a 5GHz frequency there is no overlap between any of the channels. Which is not the case for 2.4GHz and also there's much less crowding of frequencies in transmission of each of the channels, since5GHz is used less than 2.4GHz.
So overall it opens more bandwidth that is able to be used on each individual channel of the Wi-Fi and that along with improved protocols for transmitting data such as being able to use multiple streams on different channels just makes 5GHz faster.
The 2.4GHz ranges is very crowded and used by many other household devices. It's not just Wi-Fi which takes up a lot of airspace, like cordless phones, Bluetooth, even car alarm sensors and microwave ovens all of these are in the same 2.4GHz range as Wi-Fi, and that just crowds the space and makes it tougher for the signal to get through.
All this interference could potentially results in packet loss, poor signal. But it's not the case with 5GHz. Very few devices use the 5Ghz frequency in your house. Which is certainly less than 2.4GHz, that means that you will have a much stronger signal and more availability of each channel.
2.4GHz Signal Range > 5GHz Signal Range
The main disadvantage of 5GHz, is it has a significantly shorter range than 2.4GHz. In general, lower frequency radio waves are able to pass better through walls than higher frequency waves. So if you are away from the router, you probably going to have a stronger signal with the 2.4GHz compared to 5GHz.
Every environment will be different. For example, you probably want to consider the type of devices you are using. If you're using something that doesn't require a lot of speed, but rely more on the signal strength then 2.4Ghz is best suited for you. Here you will get consistently a better signal.
Now another important thing to note between 2.4GHz and 5GHz is the type of protocol you are using. If you're using 802.11AC, that only uses 5GHz. It doesn't support 2.4GHz which is backwards compatible. But if you're connecting, a 2.4GHz to AC router, then it will only be using 802.11N not 802.11AC. If you want to take advantage of the AC protocol, it has to be 5GHz.
Wireless N on the other hand support both 2.4GHz and 5GHz. Hence, if you are using 2.4GHz channel with an 802.11AC router, you are not fully enjoying you Wi-Fi connection.