In order to prevent ads from sneakily using visitors’ computer resources, Chrome developers are working on limiting the resources a visual ad can consume before a user interacts with it.

The first time this issue came to light was in 2017 when developers and cybersecurity personnel noticed how a swarm of sites and ads were using users’ computer resources to mine bitcoin and other cryptocurrencies.

According to Google, these ads only comprise of 0.3% of the total ads, but they account for 28% of CPU usage and 27% of network data, which is a lot. The only signs that users see are whirring fans, drained batteries, and increased network consumption.

Recently, Google published a blog post detailing that its developers have measured a large sample of ads that Chrome users encounter. The company writes that ads that use more CPU resources or network data than 99.9% of overall ads will be blocked. In technical terms, this translates to 4 megabytes of network data or 15 seconds of CPU usage in 30 seconds.

Chrome Project Manager Marshall Vale wrote in the blog:

We have recently discovered that a fraction of a percent of ads consume a disproportionate share of device resources, such as battery and network data, without the user knowing about it. These ads (such as those that mine cryptocurrency, are poorly programmed, or are unoptimized for network usage) can drain battery life, saturate already strained networks, and cost money.

These limits will be imposed over the next few months in the beta version before being added to the stable version of chrome. Chrome users who want to turn the feature on sooner can enable it by pasting “chrome://flags/#enable-heavy-ad-intervention” in their search bar and choosing the disable option relating to the resource-heavy ads.