First post, by EverythingOldIsNewAgain
A story has been making the rounds the past few days that Adblockers, in particular AdBlock Plus, may - counter-intuitively - actually gobble up your memory and CPU cycles:
Mozilla's Nick Nethercote got the ball rolling:
wrote:AdBlock Plus (ABP) is the most popular add-on for Firefox. AMO says that it has almost 19 million users, which is almost triple the number of the second most popular add-on. 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.
But we recently learned that ABP can greatly increase the amount of memory used by Firefox.
First, there’s a constant overhead just from enabling ABP of something like 60–70 MiB. (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....
The whole thing is here.
The Adblock Plus developers have responded:
...Now, there are really two very different issues mentioned there. One is caused by very non-obvious behavior in Firefox: while Adblock Plus registers a single stylesheet for its element hiding feature, what happens behind the scenes is Firefox creating a new copy of it for each page being loaded (bug 988266). The memory consumption of all these copies can be very significant, like the 2 GB mentioned above for an edge case....The other issue is the memory consumption of the data structures created by Adblock Plus itself, these are mostly required in order to manage and apply its filters. Current filter lists for Adblock Plus have around 50 thousand filters which (along with supplemental data like filter hits) require around 60 MB of memory. Clearly, that data is stored in a less than optimal way but apparently that’s hard to avoid when working with complicated JavaScript objects.
Full thing here.
The same principle applies to Chrome. I have to say, while I easily buy the memory usage scenarios, the part about CPU cycles I find a bit more perplexing. I've seen what the modern web looks like on an old machine with and without Adblock and there's just no comparison. I'm a bit surprised that something that's supposedly stressing the system more would make pages load smoother.
Of course if you really want to see something painful, load IE7 or 8 with its ancient JavaScript renderer onto an old computer and may the hourglass be with you. (Ironically, IE's "Tracking Protection List" filtering doesn't actually seem to eat memory...)
