MacOS Sierra - Safari has 300% CPU

I am also having this issue with Safari, and I've disabled all the extensions I have running... so I am beginning to be worried...

Hello spazio-keeper,
Thank you for using Apple Support Communities. It's my understanding that Safari is using a larger than normal percentage of the CPU, impacting your MacBook Pro fan. I know it can be concerning when apps and the fans behave unexpectedly. I am happy to help.

First, I recommend quitting the app by opening Safari choosing Safari > Quit Safari. If the issue persists the next option would be to reset the System Management Controller (SMC). This can resolve performance and fan issues. Use the steps and link below to assist with resetting the SMC.

1. Shut down the Mac.
2. Plug in the MagSafe or USB-C power adapter to a power source and to your Mac.
3. Using the built-in keyboard, press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time.
4. Release all keys, then press the power button again to turn on your Mac

Reset the System Management Controller (SMC) on your Mac
Have a great day!

It's not the fan. It's processing! We see it on the Activity Monitor.

Several Safari Web Content consuming 100% and every tab is consuming 100% too.

It happens when i start Safari.

If i quit it, the CPU calms down.

By the way, i've done the Reset of SMC and nothing changed at Safari consuming CPU.

Here is an screenshot of the Activity Monitor

Looks like your "wise.com website Plug-in is a problem page for Safari, just a guess

Don't think so, as mine is also suffering from the same issue...

Close Safari and CPU level drops to normal. Use another browser and CPU is still normal. Have also performed the SMC reset and disabled all extensions - all to no avail.

Nope, that happens with any website, even apple.com

Same here. CPU at 99% or higher. RAM climbs continously, stopped it at 65 GB. Extensions disabled, no new installed recently. MacBookAir runs hot very quick.

Sierra installed 12 hours ago.

If you have Trusteer Rapport Endpoint Protection installed remove it.

I'm glad I'm not the only one with this issue. I did a clean install of Sierra via USB drive and not an upgrade.

Early 2011 13" MacBook Pro

2.7 Ghz i7

16 GB RAM

I think that the issue resides in the Safari Application itself. I have trashed all folders containing any content for Safari, and a restart of the Safari Application will yield a usable program for NO MORE THAN 60-120 second.

I don't even have enough time to read the cpu usage in the Activity Monitor.

If it doesn't work will all user content removed, then I don't think we should be directed to use time consuming procedures to troubleshoot the problem until we hear from Apple.

I've spend over four hours on this issue today and that is four hours on work that I'm not getting paid for because I was wasting my time on Safari.

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