Chrome for Android will soon support DNS prefetching, a technology that allows for faster web browsing. DNS prefetching, which is also known as asynchronous DNS, was hidden deep within the options in the desktop version of Chrome since 2012 when it was introduced as a feature and disabled by default. Thanks to some excellent work by some developers, it can now cut page loading times by up to a few seconds.
When you visit a webpage using any web browser, it queries a Domain Name Server (DNS) to get the IP address of that webpage. It’s to eliminate the need to remember IP address numbers for different websites, to save you the trouble of having to type out the IP address of a website into your browser’s URL bar every time you wanted to visit it. Which is why every website’s domain name is linked to it’s IP address and the data is stored on DNS servers, located across the globe.
DNS servers around the world keep a database of websites and their associated IPs. When you’re browsing the web, the DNS lookup process can take a few seconds in many cases, which leaves folks with fast connections waiting for servers to finish name resolution and return a website’s IP address, significantly increasing page load times.
With the DNS prefetching flag enabled, Chrome scans the page for clickable links and resolves the URLs to IP addresses on a real-time basis. A good example where DNS prefetching can help is when a user is looking at a page with many links to various websites, such as a search results page.
When the web browser encounters a hyperlink that does not share the same domain name as the current location, it first checks its cache and then resolves the domain to the associated IP address through a request from a DNS server, if the cache is devoid of relevant data.
These processes happen in the background to not block the loading of the page. Since all this takes place in the background while the user is reading the page, it places a negligible load on the system resources.
However, it is very likely going to be disabled by default, and one would have to dig deep within the chrome://flags page to enable it.
Source: XDA Developers