To get this to work, Chrome will keep track of the amount of resources an ad uses. An ad will be considered resource-heavy if it uses:

the main processor thread for more than 60 seconds in total,the main processor thread for more than 15 seconds in any 30 second window, ormore than 4MB of network bandwidth

When the browser detects that an ad is guilty of one of the above, then the browser will block the ad. An error message will be in its place instead, explaining why the ad was blocked. Unfortunately, there’s no indication as to when this will be implemented into the standard Chrome browser. You could give it a try if you don’t mind experimenting using Chrome Canary, as long as you expect it to not work perfectly. (Source: Google, GitHub via 9to5Google, Techdows)

Google Chrome Browser To Stop Ads That Take Up Too Many Resources - 37