After Google announced Public DNS to speed up URL resolve time, Google Analytics rolled out a new tracking technology called Asynchronous Tracking. There are reports from webmasters that Google Analytics tracking code can sometimes stop responding and slow down the overall load time of the website.
WordPress users: To set it up, make sure you have entered the code before the tag in Header.php file as shown in the screenshot below. You will need to replace the old code with this new code but make sure you have noted down the User Account(UA) number which goes like UA-XXXXXX-X. You will have to enter this UA in the new code.
Every Analytics user have a unique User Account number so make sure you enter it correctly. After implementing this new code on my site I have observed slight increase in speed, but it is so slight that it is not observable to an average user.
Also please note that if your Analytics code fails to load sometimes, it won’t effect the web page. In other words, your web page will load just fine.
It is recommended that every webmaster should enter this new code if they want to speed up Analytics and improve tracking.