In particular, if you hear people complaining about Firefox’s memory usage, one of the first questions to ask is whether they have ABP installed. In the meantime, it’s worth keeping these measurements in mind. I hope that the ABP authors can work with us to reduce this overhead, though I’m not aware of any clear ideas on how to do so. But if you’re using a low-end machine without much memory, you might have different priorities. Many people (including me!) will be happy with this trade-off - they will gladly use extra memory in order to block ads. So, it’s clear that ABP greatly increases Firefox’s memory usage. Unsurprisingly, the page also loads more slowly with ABP enabled. This is despite the fact that ABP prevents some page elements (ads!) from being loaded.Īn even more extreme example is this page, which contains over 400 iframes. With ABP, that number more than doubles, to 417 MiB. For example, if I load TechCrunch and roll over the social buttons on every story (thus triggering the loading of lots of extra JS code), without ABP, Firefox uses about 194 MiB of physical memory. Many pages have multiple iframes, so this can add up quickly. Second, there’s an overhead of about 4 MiB per iframe, which is mostly due to ABP injecting a giant stylesheet into every iframe. (This is on 64-bit builds on 32-bit builds the number is probably a bit smaller.) This appears to be mostly due to additional JavaScript memory usage, though there’s also some due to extra layout memory. I have happily used it myself for years - whenever I use a browser that doesn’t have an ad blocker installed I’m always horrified by the number of ads there are on the web.īut we recently learned that ABP can greatly increase the amount of memory used by Firefox.įirst, there’s a constant overhead just from enabling ABP of something like 60–70 MiB. AMO says that it has almost 19 million users, which is almost triple the number of the second most popular add-on. AdBlock Plus (ABP) is the most popular add-on for Firefox.

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