Safari Web Content Hogging RAM and CPU Time, Thread on Apple Support Communities

I have noticed on my MacBook 5,1 with 4 GB of RAM that Safari gets sluggish in full screen mode with twelve tabs open. I also noticed that Safari 5.1, which ships with Mac OS X Lion, spins two processes: Safari (currently using 294 MB RAM and 6.2% of CPU utilization) and Safari Web Content (currently using 1.33 GB RAM and 41% of CPU utilization). If I drop out of full screen mode, the RAM allocation remains the same, but the CPU utilization drops to about 1.4% and 8% respectively. Now, I am back into full screen mode, but I have not yet seen the spike in CPU utilization. I currently have three Safari Extensions installed: AdBlock, Awesome Screenshot, and Click to Flash. I also have the latest version of Adobe Flash installed, but I do not have any active Flash content loaded.

I searched online to see if anyone else is having similar issues. I found a thread started by scryedz on the Apple Support Communities, who began the discussion by writing:

Hi everyone! Safari become very lag when I open a new tab or pages, and when I checked Activity Monitor, the one that made my mac lag is Safari Web Content, it can eats 80-90% of CPU.However, it only happened if I open new tab/pages. I never experienced lag with other browser such as Firefox before. Anyone ever experienced this? Any suggestion or solution will be appreciated. Thanks.

via Safari Web Content high CPU usage: Apple Support Communities.

Following the thread, it sounds like others are experiencing Safari’s resource hogging and system sluggishness. Some suggestions to fix the problem include deleting Safari’s cache files manually (~User/Library/Cache/com.Apple.Safari) and uninstalling all Safari Extensions.

Hopefully, Apple will address this problem more assertively with a software update to Safari.

Published by Jason W. Ellis

I am an Assistant Professor of English at the New York City College of Technology, CUNY whose teaching includes composition and technical communication, and research focuses on science fiction, neuroscience, and digital technology. Also, I coordinate the City Tech Science Fiction Collection, which holds more than 600 linear feet of magazines, anthologies, novels, and research publications.

10 thoughts on “Safari Web Content Hogging RAM and CPU Time, Thread on Apple Support Communities

  1. 1. we dont see the screen shot.
    2. It’s interestesting that there’s only these 2 comment here rather than about 200,000 or so since every mac running Safari will have this problem unless there is a fix everyone is using but there doesn’t seem to be.
    3. I have read other site’s thin discussions on this same issue and none seems to have anythin near as mosest as 748 combined use of RAM for the Safari and Safari Web Content, it’s usually well over a Gig for just Safari Web Content which is what Ive been experiencing on all my computers when running safari. Restarting it does nothing except lower the Safari Web Content for less tha a couple of minutes then it’s back up to the same amount: more than most computer shppied w/ in recent times.
    Apparently Safari “sucks” ( to para phrase what could otherwise be a lenghty article) as do apple computers; the only reason we use them is because PC”s are much much worse. So we accept crap, because tehre’s no better alternative. Even Steve Jobs found enough problems w/ tehm that he came out w/ some thing new: NEXT. He tried to bring that to apple when he got his job back there.

  2. possible retraction on Safari “sucks” point above, I just read a good answer to the Web Content issue, apparently it’s for security and stability, read:
    “Mac OS X Safari Web Content Process
    Or, why is Safari Web Content eating my Mac’s memory?”
    its from :

    closes article w/:
    “And, as a nice extra: if some script on some website hangs your browser, you can kill the Safari Web Content Process, and can continue surfing without having to close Safari and all your open tabs!”

    still, apple has a lot to fix w/ their operating system. And “web content ” as nice as it seems is a pretty expensive safety net using over a gigabite of RAM.

  3. It’s really annoying to see so many comments on the web by people that have a genuine problem with new MBP’s, noisy fans and crashing Safari sluggishness is a total pain. Not least as I need a new laptop and have been seriously thinking about ditching Apple after 13 years.

    That this issue doesn’t seem to effect the majority of Macs… I would counter that not everyone needs 20 tabs open. Some people do. (Journalists/writers researching etc…) My CPU however can hit over 100% with just 4 tabs open, after a few hours I will have to restart the browser or suffer performance reminiscent of internet dial up in 1997.

    Apple Tech 2 Support in Ireland couldn’t permanently fix this known issue with high CPU/racing fans and eventual crashing of Safari. I had it from day one when I was “upgraded” from a Powerbook (it had fatal issues) to a 2006 Macbook “Amateur.” The problem was so bad that I installed Parallels and used Windows XP Internet Explorer without any issue. The problem seemed to go away years later with an update only to come back with another update a year or so after that (2011).

    To date they still haven’t honoured the original service plan warranty with a permanent fix, but hey that’s just Apple… nevermind that fact that I have lost a hideous amount of time because of their problems, neither have I ever been given any kind of explanation, except most people know now that this is an issue with how Safari handles Macromedia Flash. Hence clicktoflash….

    That Apple continue to charge a high price and yet their computers are no better than Windows based PC’s says a lot about the the fact that Apples are based on style and feel more than performance? (Discuss). Watching a youtube vid involves having to listen to noisy fans or suffer glitching or eventual freezing/browser and restarts.

    If these comments seem to imply the feeling that I have a “problem” with Apple please note: I have had 3 replacement laptops from Apple. Every single one had a combination of all these problems: Hard Drive fatal crashes/Hardware failures/Battery issues/Screen faults/Motherboard failure/DVD drive replacements etc. Continual unreliability. Over 20,000 business emails in Apple Mail is the only reason I still use Apple and unfortunately will have to continue with them. (Yes I know they can be converted but then do I want to deal with PC viruses/continual updates/virus checks/subscriptions?)

    Because Apples business model only works on having products that have relatively short lifespans and getting their customers to shell out over and over again because they make their computers vintage after 5 years (finally resulting in no parts/no support) and continually upgrading causing conflicts with older hardware/software, probably explains why they’re sitting on $90BN of cash offshore that they haven’t repatriated because the US tax authorities will take approx 30% of it. Foxconn worker suicides and the signing of worker non suicide agreements (to mitigate higher compensation payouts in the event of suicides) are another blight on Apples once excellent reputation.

  4. It seemed (in my very limited testing) that part of the problem was on older Macs.

    I have a MacPro 1,1 and Safari slows my whole machine down…. But only since upgrading to v6 on Lion. But the situation seems to be not anywhere near as bad on my wife’s 2011 iMac.

    I have run Cookie, cleared caches, run the correct extensions, removed flash etc, etc, but basically until there is a fix for this performace problem I had to move to Chrome temporarily. Sad. Chrome is nice and all, but not ‘nativey’ like Safari.

    I thought it was a memory leak, but in my thinking it must be a random process leak… Anyhow, the upside is that I have deleted over 1000 cookies that I didn’t know were hiding on my machine. The downside, is that I constantly feel like looking over my shoulder at the company that collected wifi data illegally.

    I’m downloading the latest nightly build from to see if that will make any difference. But I have a feeling that it might be a system problem (Java, or security, or, or, something) that is conflicting with Safari on my Mac….

  5. Hi Aaron,

    Thanks for stopping by!

    This is interesting that the problems that I described might have reared their head with the new version of Safari on Lion. This is even more surprising to see on such strong hardware–particularly your MacPro.

    My wife is running MacOS X 10.7.4 on her 13″ 2009 MacBook Pro with 8GB RAM, and she has not told me about any problems since she upgraded Safari to 6.0. However, she splits her browsing between Firefox and Safari, so I don’t know what kind of time/energy she has given to testing out the new version of Safari on Lion.

    I haven’t experienced any trouble with Safari 6.0 on Mountain Lion on my late-2008 MacBook with 8GB RAM. With the limited time that I have devoted to using my MacBook, I have not had any slowdowns on the system. In fact, everything from Safari to Word seems snappier.

    I think it is very cool that you are trying out the nightly builds of Webkit–I had not considered doing that on my Mac when I first experienced the problem. If things improve or get worse, please post your results.

    I wish that Apple would release Safari 6 for PCs, because I am now using a Windows 7-based PC that I built this past weekend. So far, Apple has been mum about why they did not do a simultaneous release of Safari 6 for Mac and PC. I noticed that the iCloud control panel on Windows does not offer a bookmark sync option, so I wonder if they plan to kill Safari support for Windows. I hope that this is not the case.

    Good luck!


  6. The only problem I have with Safari eating up resources is when my Facebook page is open and my 2010 Macbook Pro goes dormant.
    To solve this, I close the Facebook tab and everything goes back to normal, but yesterday was a particularly ‘fine’ example.
    I got back from doing some yard work and my Mac was exceedingly slooooooow. Safari had hogged 6 of the available 8 GB and was using up half of the processor capacity. When I finally got the Facebook tab closed down (took me about 10 minutes), everything went back to normal.

    Has anyone else seen this behavior?


    Macbook Pro 2010
    OSX 10.8.3
    Safari 6.0.3

  7. Klaas, I have actually seen that exact behaviour. Closing the Facebook tab helped. I actually just moved from Chrome to Safari for the same reason, but it obviously did not fix the issue. It must be related to something that is the same in both browsers, like a Flash add-in.


  8. Klaas and Rene, did you have the “Fasttube” Safari Extension installed. Removing that helped me with that Facebook problem.

  9. I just upgraded my rather old iMac to Snow Leopard and then did the same to Safari 5.1.10, but ever since I did that I haven’t been able to connect to internet because the Safari Web Content process kicks in and kills everything….when I open a new window or tab, it just goes blank and keeps trying to load content and after a while I get an error message… Any ideas on how to prevent that process from running or how to bypass it??? I wish I hadn’t upgraded it!!!! it worked just fine before, although some pages required me to upgrade
    Thanks for your comments!!!

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