LinkedIn uses +90% of the CPU in my brand new MacBook Pro.

Are you running any anti - virus programs? Using a VPN?

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Strange. I just loaded LinkedIn (it's still open in the background, signed in and on my main feed). You're right. Activity Monitor shows the LinkedIn.com tab process using about 40-50% CPU on my system, but only when it is onscreen (around 1% when offscreen). The messages that continue to appear in the Web Inspector are connected to the content blocking:

[Error] XMLHttpRequest cannot load https://www.linkedin.com/sensorCollect/?action=reportMetrics due to access control checks.
	(anonymous function) (cxd2w8dc46mljy1q2at78n61o:1272:99)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:8912)
	e (bkorl7rcuut3nfx5ymwc9jbjq:8914)
	E (cxd2w8dc46mljy1q2at78n61o:1257:82)
	value (cxd2w8dc46mljy1q2at78n61o:8278:119)
	(anonymous function) (cxd2w8dc46mljy1q2at78n61o:8278)
	E (bkorl7rcuut3nfx5ymwc9jbjq:8858)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7595)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7572)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7610)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7739)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7666)
	(anonymous function) (bkorl7rcuut3nfx5ymwc9jbjq:7765)
	(anonymous function)

Edit: To be fair, I tested LinkedIn.com without any Content Blocking. The CPU usage was the same. So it's not Adguard causing this latest CPU usage. It's their poorly-coded site compatibility with Safari. Does anyone have Safari 14 to test if it's any better?

@umparrothead Thank you that resolved the issue for me. I'm using Adguard, and I added https://linkedin.com/li/track to the whitelist and now the CPU is no longer spiking.

@BL5577: On my MBA, Firefox seems to use the least CPU on LinkedIn. Still not great, but it's apparent we can attribute it to issues within their own site.

@dk401 Thanks for explaining how to manage the issue. (I opened Ad guard extension in Safari, clicked the wheel, clicked tab for whitelist, added https://linkedin.com/li/track). My CPU usage wasn't eliminated, but it did go down and the fan stopped running.

I'm having the same issue too with Safari, brand new Macbook Pro (top spec, 32GB ram), issue happens in Safe mode as well, no VPN or anti-virus running or any other applications. Does not happen in Chrome or Firefox, only Safari.

Had the same issue. Traced it down to their tracking code being blocked and not handling that well. See my GitHub report on it: https://github.com/AdguardTeam/AdguardFilters/issues/59382 Now LinkedIn uses 5-10% CPU (still not great but a ton better). Confirmed in Firefox (with uGuard) and Safari on Catalina.

Yes, I've been having this issues consistently for months. Happens both on Safari and Chrome. I don't use adblocker so not how this solution would help me. No other website or app causes my MacBook Air to heat up and kick the fans on like LinkedIn.