Google Chrome will start unloading ad iframes using too many system resources starting with the end of August. Chrome will target ads that drain device resources like battery, network data, and CPU processing power, such as those designed to mine for cryptocurrency known as being resource hogs that will drain battery life and network bandwidth. Chrome is trying to steer ads into becoming friendlier with a whole range of abusive or misleading advertisements since version 71 was released in December 2018. Ads previously included in Chrome’s blacklist are the ones that promote and distribute malware, feature hidden click areas, display fake click areas and display fake mouse pointers.
Source: https://www.bleepingcomputer.com/news/google/google-chrome-will-block-resource-heavy-ads-starting-august/