Did Apple fix Intel MacBook Pro fan noise?
I noticed after the 15.6.1 that my external displays wouldn't work. I started investigating and found that something major has changed in MacOS with this "minor" update.
I clicked on gfxCardStatus and it was not loaded. Both displays came up. I went then and uninstalled and rebooted.
Displays were off again. Turned off Automatic graphic switching and guess what? The displays came back on. The fonts weren't as crisp as before so I switched my external displays to 50hz and they look good again. I then turned on automatic switching (in clamshell mode) and the displays stayed on but I noticed the fans are not on (or not annoyingly loud).
Something changed in the graphics layer, and maybe for the better.
Here is my report with the help of chatgpt including the additions that I have noted:
Title:
External displays not detected on Intel MacBook Pro 16" after macOS 15.6.1 update
Description:
After updating to macOS 15.6.1, my 2019 Intel MacBook Pro 16" (2.4 GHz 8-core i9, Intel UHD 630 + AMD Radeon discrete GPU, 64 GB RAM) no longer initializes external displays at startup.
- I use two 4K monitors through a CalDigit TS3+ dock, but the issue also occurs when connecting a single display directly over USB-C → DisplayPort/HDMI (bypassing the dock).
- Displays work normally in Safe Mode.
- In normal mode, displays remain undetected until I disable Automatic graphics switching in System Settings → Battery → Options.
- Once the AMD GPU is forced, external displays light up immediately. I can then re-enable Automatic graphics switching, and the displays remain active.
This strongly suggests a regression in GPU handoff/initialization logic introduced in 15.6.1. Before the update (15.6), displays were detected consistently with Automatic graphics switching enabled.
Steps to Reproduce:
- Boot a 2019 Intel MacBook Pro 16" on macOS 15.6.1 with Automatic graphics switching enabled.
- Connect external 4K displays (either directly via USB-C or via Thunderbolt dock).
- Observe that displays are not detected.
- Disable Automatic graphics switching in System Settings → Battery → Options.
- Displays are immediately recognized.
- Re-enable Automatic graphics switching. Displays remain functional until next reboot.
Expected Result:
External displays should be detected automatically at boot with Automatic graphics switching enabled.
Actual Result:
External displays are not detected unless Automatic graphics switching is toggled off (forcing discrete GPU).
Notes:
- Issue affects both direct connections and docked connections.
- Displays work normally in Safe Mode.
- Problem began immediately after updating from 15.6 → 15.6.1.
Additional Notes:
- I normally run in clamshell mode with two external 4K monitors. Before 15.6.1, the fans on my 2019 Intel 16" MacBook Pro (i9, Radeon GPU) would spin constantly under this setup, even when the system was mostly idle.
- After updating to 15.6.1, once the displays are recognized, clamshell operation has been much quieter — fans remain off or at very low speed for extended periods. This suggests that GPU power management / clock scaling behavior may have changed in this update.
- When initially plugging in the externals, the fans spin briefly, but then settle down once displays are stable.
- I also adjusted my monitors from 60 Hz to 50 Hz. At 60 Hz, fonts looked slightly less sharp than before the update; at 50 Hz, clarity improved. Both screens are running at full 4K resolution.
- These changes in fan behavior and display rendering, combined with the display initialization issue, point to a likely modification in macOS’s GPU switching and power management logic in 15.6.1.
Maybe this will help you too. Makes me think that Apple did this intentionally on the 2019 i9 MBP to promote the upcoming M1 launch...
[Re-Titled by Moderator]
Original Title: Did Apple Fix Intel MBP Fan noise?
MacBook Pro 16″, macOS 15.6
