Chrome: It's no secret that Adblock Plus is one of our favorite add-ons, and it does a lot of cool things. However, it's definitely memory hungry, and can slow your system down. If you want a leaner alternative that still keeps the web clean and protects your privacy, try uBlock (or rather, µBlock.)
µBlock works on any Chromium-based browser, so you can use it in Google Chrome proper, or in Chromium for other platforms (like Linux). Once installed, the app works very similarly to Adblock Plus; it'll block ads for you, uses the same lists (namely EasyList, EasyPrivacy, Malware Domains, and more—or you can add and customize your own sources to block), and overall keeps your browsing experience clean and trim. There's one notable difference though—µBlock uses significantly less resources than Adblock Plus. Of course, its feature set is also a bit lighter—it doesn't do quite everything that ABP does, but if the reason you have ABP installed is primarily for adblocking and privacy protection, it'll do the trick.
As with any extension of its type, the add-on requires heavy permissions to work. The developer explains those permissions in detail here, and answers questions about the tool and its features here (including comparing it to ABP). If you're curious how much memory you're actually going to get back his efficiency comparison is a good read, too. Hit the link below to give it a try, or read more about it over at GitHub.