Why is Safari using 97 percent of my CPU?

The last few days of my MacBook Air have been a little wonky. I couldn't figure it out until today when I noticed that Safari was using anywhere from 90-97 percent of my CPU. I also noticed a few times when the CPU was running over 100 percent.

Please note that I was using Microsoft Office, but I didn't feel good about it. We have a board meeting tomorrow and I needed to review some stuff. I still can't figure out how to get the formula bar where I want it in Excel 2008 and it makes me crazy.

I had been blaming Firefox for the machine slowdown, so my apologies to the Mozilla team.

Safari pegging my CPU

(Credit: Dave)

[smkatz]

Plugins can cause this. (Flash, perl?) Also, according to macosxhints.com, the favicons folder (~/Library/Safari/icons) and the cache can sometimes cause cpu usage. Yes, it is a leak or hog issue.. and it is vastly improved in the developer builds, which are available at dave hyatt's blog.

--Sam

[FellowConspirator]

This isn't Safari so much as it is the Flash plugin. You'll find it sometimes happens with Firefox too. This is a farily well known bug in the Flash plugin. To a lesser extent it also affects Windows and Linux too (pretty rare under Windows, but it still happens now and then).

[d.c.rogers]

I agree about the formula bar in Excel 2008!

[mreiher]

Yeah... I have a ton of things running on my MBP including Safari and the CPU is only bouncing around 5-7% of usage.... I'd say you have other factors than Safari causing your CPU to go nuts. I'd select "Reset Safari" from your Safari menu and see what happens first. What's happening to you is not normal.

[Ronin_1]

I would also suggest running a system utility such as OnyX, Yasu or Cocktail (available from MacUpdate.com or VersionTracker.com) which can clear all caches as well as running the daily, weekly, and monthly Unix functions that are not run unless the system is on (and not set to sleep) 24/7.

Safari, like virtually all browsers presently available should be restarted at least once a day or they tend to build up things.

Keep an eye out for an item in Activity Monitor named syslogd which has been reported to periodically consume very substantial CPU cycles in other Macs. Several people have been reporting going into Terminal to (temporarily) stop the process, but just force quitting it from within Activity Monitor seems to work as well. Note: syslogd is just a log file and will restart itself without further action.

[Constable Odo]

It must be a plug-in. Safari barely sips CPU cycles when I go to various sites. At one time Reuters used to suck about 50% CPU cycles, but I believe when I updated the plug-ins on my computer I was able to cure that problem. Either way, it has something to do with your particular machine and not Safari in general. On this page my MacBook Pro 2.33 with Safari is using about 3% CPU. On AOL it was using about 11%.

[Olu070]

Do yourself a favor and get a menubar utility called Menumeters (free). It has graphic symbols in the menubar. It has ones for CPU, Network activity, Hardrive activity. It's a quick way to see when your CPU is getting out of control.

[Maarek Stele]

Safari has been known to take up alot of CPU processing on any Mac. I'm sticking with Firefox.

[SWK595]

Running Mac OS X 10.4.11, on an iMac G5 with 1GB of Memory. The latest Webkit is running at five percent. Safari itself averages at eight to fifteen percent.

[lkrupp]

"Safari has been known to take up alot of CPU processing on any Mac. I'm sticking with Firefox."

Patently false, Firefox F.U.D.

[blues_coup]

" I couldn't figure it out until today when I noticed that Safari was using anywhere from 90-97 percent of my CPU. I also noticed a few times when the CPU was running over 100 percent."

This is because of a bug in the way the CPU usage numbers are calculated in the Activity Monitor. I've never really been able to figure out exactly how they are calculated but since the switch to multi-core CPUs it has been incorrect. The only reliable way to tell about how much of your CPU is being used is by the little bar graphs and how much black is showing across all of your cores. Granted this makes it impossible to tell what processes are taking up how much but you still have a ballpark approximation based upon the incorrect usage numbers.

With that said I have had Safari peg my CPU nearly all on it's own, but that is usually because of the various aforementioned poorly coded plug-ins.

[sriggins]

You might want to try running pith helmet to turn off animated ads (heh, maybe it is cnet ads!) but at least that will tell you if those are chewing your time.

[Kevplugz]

I've had the same problem with flash burning up my CPU.
It's a major issue and I can see why flash is banned from the iPhone.

[M C]

Blog now, troubleshoot later.

Sounds like CNet.

[nouser]

Safari runs between 3 and 8% on my Macbook. Something else is causing your issues.

[archseed]

This claim is patently absurd! Thanks, Barack Obama.

No, seriously, I am not using the latest Webkit and I hardly use 5% of my CPU. The author should blame Microsoft's humungous programs for his woes instead of spreading FUD about Safari.

[Walt French]

Easy to keep Activity Monitor's little bar(s) on-screen to see when something jumps.

Less easy to understand why sites like FT.Com -- otherwise, a fine business/news source -- make their sites unacceptably bad by whatever Flash / script / etc.

Not to try to understand this too much: FT (and whatever sites are sandbagging your machine) already know that their ad machines or whatever are quick & dirty CPU cycle-burners, the equivalent of Chevy Suburbans' rotten gas mileage without any comfort or power features that justify it. Or, if they don't know, it's because they don't want to know.

Don't worry: Safari is a fine browser; it just can't work miracles when a site asks it to do meaningless crap every millisecond.

[j0hnny0]

I'd like a way to see CPU utilization on each Safari page or tab that's open. That way I could zap the offending Flash applet.

Too bad Pith Helmet only does Safari 3.0.4.