High CPU usage in Chrome/Opera
Having the same issue. It's not very good even in Safari. I suspect the mtlcompilerservice, as I load pages I see a lot of instances of it in the Activity Monitor, consuming high CPU. TGPro shows high temperature of the CPU, 90+ celcius. Video playback heats up the device but loading pages and browsing around is the worst offender.
I have the 15&quot; mid 2014 model with Iris Pro &amp; Nvidia gt 750m. I thought the reason for overheating/fans-kicking-in-whenever-they-please was that Apple changed some things as to how GPUs work in Big Sur.
I'll try installing Big Sur to a separate volume, and if that doesn't help, I'll re-install macOS, starting from High Sierra and update here.
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Idle temp: 54-60 C  Browsing: 70+ C