Safari Web Content high CPU usage

Seems like your prayers were answered. John Siracusa in an ArsTechnica review: "The most important changes to Safari in Mavericks are internal. Two years ago, Lion included a version of Safari based on the WebKit2 engine, which separated the task of page rendering and JavaScript execution into an external process, mostly for security reasons.

WebKit2 was a reaction to Chrome's multi-process architecture, which uses multiple WebKit processes to handle page rendering. Google included the multi-process code in the Chromium project, not in WebKit. Before creating WebKit2, Apple asked Google if it was willing to contribute Chromium's multi-process code to the WebKit project. Google declined, leaving Apple to create its own solution. Apple implemented its multi-process system in the WebKit engine itself, benefiting any application that uses WebKit.

Unfortunately, the WebKit2 era of Safari has been marred by chronic instability. When Safari's lone back-end Web rendering process gets wedged, users are greeted with the all-too-familiar "webpages are not responding" dialog; forward progress requires reloading every open webpage in every tab in Safari. This problem has not gone away in the years since Lion was released.

Contrast this to Google's Chrome browser, which has been rock-solid over the same period. The cumulative effect of these years of Safari instability has made me start to question whether Apple still has the chops to keep up in the fast-paced world of Web rendering engines.

Safari version 7, included in Mavericks, is Apple's answer. It sports a new process-per-tab architecture, finally following in Chrome's footsteps—though this change is part of WebKit itself, not just the Safari application. It's too early to tell if this change will restore Safari's stability, but I can report that I have not seen a single Safari crash or "webpages are not responding" dialog in all my Mavericks testing. (I've seen many in Safari 6 while writing this review in Mountain Lion.)"

This may also be a reply to those who say to Apple, "just fix it"; Apple's been obviously thinking about this for years. It's kinda like you want your '64 Ford to run like your Prius - it ain't gonna happen in one day.

Read the rest of the Safari review, and then read the rest of his review: http://arstechnica.com/apple/2013/10/os-x-10-9/4/

Great contribute indeed, John!
Eager to try Safari 7 (and Mavericks) full of expectations, it was unfortunately abother disappointment; it freezes and i just had to force quit ANOTHER TIME MORE!
I'm writing you using Chrome 30, which still has huge 'page not responding issues (but has a hundreds time nicer interface, starting by the bookmark bar, where I put just the colorful favicons without ant character, easy and saving space! Once more I'd like to state that the silly policy of greying all the icons in Mail, sidebar and, generally speaking the horrible 'brushed metal' look after the wonderful 'aqua' of the Jaguar!) and I'm trying to like Opera.
In this moment, after relaunching it, Safari shows a totally transparent page (on it's 'desktop' I can just see the 'shadow' arounf a 'glass' showing perfectly and completly Maverick's wave, without any frame, bar, whatever! Incredible, newer saw someting like that!

I read carefully any single contribute to this discussion AND NOT because I love Safari (in fact its graphic user interface is siscouraging dumb!) or I had any reason to use it, but because I LOVE APPLE, I LOVE Mac, i LOVE ALL OUR OPERATING SYSTEMS and even many wonderful softwares (the TOP was AppleWorks! But what about MacWrite for exaple?) and I'm following worried any sing of deep weakness on this field!
I was SO HAPPY when Steve introduced Safari, iTunes, iWeb, Sherlock and still can't live without Mail (and Contacts, both so much needing hard work and stood basically untouched by 10 years or, like iTunes, growing worst or abandoned like iWeb) and even iPhoto!

But we must admit that too often the software developement department shows incredible leadership weaknesses, products are discontinued or the evolution goes in a fully wrong direction without that they care, notice, listen at us… not POWER user by 'heavy users', humble people who uses for 10 hours at day our Mac to do anything and more day by day! More for productivity than for fun, to be clear and who needs much more than an iPad or iPhone!
Safari is an example of 'distance' (if not contemn!) for that kind of users, once upon a time called 'evangelists'!

I hope that some Safari developer, once ended to clean his nails in the office dreaming his next vacation, will be so bored to read your report and apply the result of your 'discovery' and wake up his coleagues from thier deserved sleep in the office, to repair this bug, just to do something new and exciting like working!

That's great, and how would I find whether I have An XBMC download link? And what or where is one's "reading list"? I know how to search my bookmarks, but wouldn't know where to look for a reading list, or what an XBMC download link is.

Do you think only that, or that kind of link is at fault, or can there be many other ones, fouling up Safari's performance? .... thanks

XBMC = XBox Media Center! All I'm saying is a download link was what confused Safari! Reading list is a list of we pages safari makes available for offline viewing/ reading later! It's shown in bookmarks tab by a pair of spectacles! Clear your reading list and see if anything improves!!

I'm not getting the CPU load issues but saferi is eating my ram since the upgrade.
I have a 4gig of which OSX is chewing 2gig but saferi is chweing through 1.78 gig !
I have disable my only plugin (Ad block plus) and it made no differance. I am trying to write a book and research and my ram with just safari, scriviner and pages hovers at 3.85/4gig ram

Am I being forced to get the 8 gig upgrade or is there something else I can do?

If you upgrade to more RAM, the operating system and Safari will snack away at it too. Depending on your system it may not be much help. It may delay slow downs but won't fix it. The logical reasoning is that if the RAM is there, let Safari use it. That's all good and well, except for the fact that - for reasons unknown - Safari will slow down gradually and become unresponsive even once it uses over a GB or a couple of GB, depending on configuration it is noticeable earlier or later, and even crash. I've got 16GB of RAM now and Safari is still a pain in the rear, exhibiting the same slow down issues that date back to when it first came out!

The only easy advice is to keep an eye on system resources via activity monitor, or a menu bar utility.

Quit Safari if you notice it isn't responding optimally any more (this should kill the Safari and Web Process sibling). Start it back up.

Shut down your system every few days. (which should set RAM use back to minimum).

Personally I tend to split the web load over various browsers, to eliminate issues with loss of tabs, history, etc and treat Safari as the disposable browser. Or I'll quit Safari before I start doing something new that's important, if I see Safari and Web Process are dragging a load.

You're so right, I do much the same, reboot the Web Content (altho Safari now does it all the time, even when it's not running up too much RAM or slowing down), reboot Safari, shut down my computer now & then, in other words, like someone with a debilitating illness, I "make adjustments" so it can function, as ravenous a RAM user as it is....

I have a brand new Retina Macbook Pro, running Mavericks. It has 16GB RAM.

Whenever Safari is running, there is an instance of "Safari Web Content" that runs at 100%. If I quit Safari and open it again, the process comes back immediately.

With Safari doing this, I get only about three hours battery life - a far cry from the "all day" promised by Apple. If I quit Safari, then the battery meter will show over 8 hours on a full charge, even when running an intensive application like Aperture.

This has been the behaviour of this machine ever since I took it out of the shrink wrap just over a week ago.

OS X version 10.9

Safari version 7.0

I look forward to Apple issuing an update that fixes this issue.

Clear your reading list! See if it helps!!! There may be a download link or something in there!!

I had exactly the same issue!! 100% CPU on Safari Web Content. the site causing it was an oxford university Mirror hosting site.. I reset safari.. nothing. I formatted my HDD and clean installed mavericks. opened safari with just my Apple ID registered... nothing changed! after a minute or 2 it was 100 % again.. spoke to many tech guys and nobody could figure out what it was!

I was sat at my mac this morning making another Install USB for mavericks and decided to clean up my bookmarks and reading list entries..

There it was!! An XBMC download link in my reading list!! Deleted it and PROBLEM IS SOLVED!!

This has done my head in for a few weeks! been using google chrome ever since! ive now deleted it and i hope this can help others figure out the issues with their own machines!!

Hope this helps you guys!!!

Stuart

Well, I checked, and I have zero items in my Reading List, so that's another dead-end for me. I'm so tired of Safari slowing, freezing, crashing, and since I updated to 10.1.10, the darn thing will reboot the Web Content all on it's own, even when I'm not experiencing any slowness, which is super frustating, as I'm often in the middle or writing stuff, and it just refreshes, losing everything I've just done. *** APPLE??? This is no way to program a browser, I have no problem with rebooting the Web Content MY SELF, when it gets too bogged down, and can't stand it doing this so arbitrarily and so often!

I have been experiencing the exact same problem very recently. MacBook Pro late 2009 updated to Mountain Lion and Safari 6.1 & 8GBytes of RAM, previously with no issues. I tried numerous suggestions above (all except re-installing OS X) and even just one tab would max CPU usage. Installed Chrome - no problems at all.

Decided to power cycle MacBook - not something I do very often at all - problem goes away on Safari now. Eleven tab on a single window and % usage around < 10% for Safari and Safari Web Content combined.

Now to see what triggers the rise in CPU usage. I run iStat Menus which puts a little CPU usage widget in the top bar so I don't have to keep looking at the Activity Monitor to spot any rise in CPU usage.

Will be fascinated to know what is causing this

I deleted the two items in my reading list - no improvement.

However, I think I have found a solution:

In the Privacy tab of Safari -> Preference, click the button to "Remove all website data". Accept all options to delete everything.

My Safari now behaves as expected, without running the CPU at 100%.

Cheers,

James.

It's obvious from the comments in this thread, that there are several different causes for this problem. Having tried several of the solutions mentioned above, it turned out that, for me, the problem - stuck on over 100% cpu, often on several Safari web process - was caused by Trusteer Rapport.

Rapport is a security app, offered by some banks.

The Rapport app itself used very little cpu, but seems to have interacted with Safari to cause the high cpu percentages. Once Rapport was removed the % has plummeted to almost nothing, and a day later it's still way down.

The easiest way to remove Rapport is to use the uninstall app, which can be downloaded from:

http://www.trusteer.com/support/uninstalling-rapport

Thanks for that CDAH, I just removed Rapport from my MBP (mid-2010) and can confirm that cpu usage dropped to almost zero. Ironically I am also running Rapport on my late 2009 iMac without any issues, so it wasn't something I even considered as a culprit.