Hi, I faced this problem since beginning. This is not specific to few laptops, but a common issue for all mac owners who has additional graphical card installed. As soon as you hook up a monitor, these laptops kick in the
turbo boost even though you don't use any graphic intensive application. Bcoz of this, it rises internal temperature and fan kicks in, which results in noise.
To turn off turbo boost, please use this app. This is very easy to install and manage. After using this, I never had a problem.
Turbo Boost Switcher for macOS. Save battery of your Mac, cool your CPU and reduce fans noise
tbswitcher.rugarciap.com
Fun fact: My company replaced two laptops for me thinking that is a issue with those laptop.
Please stop spreading that non-sense/fake news. You clearly lack the technical & scientific understanding on this issue.
The TDP of the base model CPU (9750) is about 45 Watt at base clock & the 5300M is rated at around 50W.
Intel® Core™ i7-9750H Processor (12M Cache, up to 4.50 GHz) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com
The Apple MacBook Pro is powered by AMD Radeon™ Pro 5000M Series graphics, which have 24 compute units and a memory speed of 12 Gpbs. Learn more.
www.amd.com
This means under max load on CPU & GPU (without turbo boost), the power consumption would be 45W+50W=95 Watt.
With turbo boost, the power consumption can go as high as 120W for a very short period of time.
1) The VRM chips on the 16 inch MacBook Pro are quite terrible (lack any active cooling) & barely manage around 55W of sustained power supply to CPU&GPU. By sustained, I mean after running for more than 20 minutes. With only the internal display, if you run any intense workload that maxes both the CPU & GPU, the VRM chips can supply as high as 120W of total power (battery+adapter) at the start. However, after a few minutes the VRM chips overheat and the 16" MBP prioritizes the GPU. This means the CPU can get throttled to as low as 0.8 GHz. However, this by itself is not an issue for most people as most don't max out the CPU & GPU at the same time. But...this is why the Thermal Pad mod can dramatically improve performance by letting the VRM chips sustain as high as 80-85W of Power.
2) When an external monitor is connected, the GPU by default draws 18W of power. Any extra load on the GPU causes even more power draw upto a total of 50W. This means less power available to the CPU and the CPU starts throttling below the base clock to as low as 0.8GHz (Kernel task occupies something obscene like 500-1200%).
3) If you install Xcode -> Instruments, you can disable cores of your Intel CPU. Turning my 6-core i7 into a 2-core i7 reduces the power draw by quite a bit, but the performance takes an absolutely massive hit. Only recommended for the absolute desperate (who might wanna just surf the web or type emails) with an External monitor+Internal Monitor setup. This is not fix kernel_task under full load though.
4) Monterey Beta 4 & 5 did fix it. Apple wouldn't accept it, but the Engineering department clearly knows after hearing at least 100s of complaints against the 16 inch MBP. Obviously, nothing can fix the VRM throttling I mentioned in point 1 that occurs when you max out the load on GPU+CPU. That's just poor engineering when they provide no cooling mechanism for the VRM chips. I don't see Apple ever accepting their design mistake unless they face a class action lawsuit. In that case, Apple would just announce "A very small percentage of our 16" MacBook Pro customers might face diminished performance under heavy workload & external display. The vast majority of our 16" MBP customers are perfectly fine with no problems whatsoever."
P.S. Regarding the 99 Watt-hour battery & 96W power adapter. 99 Watt-hour is the battery's capacity: the total energy. 96 W is the Power the adapter can supply. The battery can supply additional power and the Laptop can consume as much as 130W total (in which case the battery will start draining slightly).
so i will not spam anymore 
