So, I got this new 2019 16" i9 MBPro recently and I started using it as I did with my old one, i.e. almost always with the closed lid, connecting external monitor/keyboard/trackpad/headset (through an USB-C docking station).
In the spirit of helping it out with the thermal dissipation in some moments, I've tested to open the lid. I know all the active cooling works the same with lid open or closed (intake air vents are on the side and outtake airflow goes on the back under the display hinge, either open or closed).
But being an engineer, I know the aluminum chassis is an heat dissipator as a whole by itself (including the keyboard area), so that's why I thought opening the lid would help.
Instead ... looking at iStat Menu sensors, I can attest that fans runs much faster with the open lid than the converse. As I write this post (and doing only this), they're running at about 3K rpm while doing the same with the closed lid keeps them at their minimum, around 1.6-1.8L rpm.
And this happens even keeping the Mac's display off (brightness down to zero), either with mirroring display or not.
How can this be explained? Can it just be the fact that the Mac is driving 2 displays rather than 1 ? It certainly requires more energy: I can see iStat Menu Radeon High Side sensor showing about 8W consumption with the lid closed, and around 18 with the lid open. So would this "thermally" cost more than the benefit of the added dissipation by opening the lid ?
And, by the way, out of curiosity, it seems that dimming to zero the Mac's display brightness (totally dark) while using the external display is irrelevant in terms of power consumption still measured at Radeon High Side (and CPU package GPU) and thermals.
In the spirit of helping it out with the thermal dissipation in some moments, I've tested to open the lid. I know all the active cooling works the same with lid open or closed (intake air vents are on the side and outtake airflow goes on the back under the display hinge, either open or closed).
But being an engineer, I know the aluminum chassis is an heat dissipator as a whole by itself (including the keyboard area), so that's why I thought opening the lid would help.
Instead ... looking at iStat Menu sensors, I can attest that fans runs much faster with the open lid than the converse. As I write this post (and doing only this), they're running at about 3K rpm while doing the same with the closed lid keeps them at their minimum, around 1.6-1.8L rpm.
And this happens even keeping the Mac's display off (brightness down to zero), either with mirroring display or not.
How can this be explained? Can it just be the fact that the Mac is driving 2 displays rather than 1 ? It certainly requires more energy: I can see iStat Menu Radeon High Side sensor showing about 8W consumption with the lid closed, and around 18 with the lid open. So would this "thermally" cost more than the benefit of the added dissipation by opening the lid ?
And, by the way, out of curiosity, it seems that dimming to zero the Mac's display brightness (totally dark) while using the external display is irrelevant in terms of power consumption still measured at Radeon High Side (and CPU package GPU) and thermals.
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