Performance has been decreased significantly after connecting via HDMI (M1)

Currently, I have some sort of performance issue with my MacBook Pro late 2020 (M1, 256, 8). I inserted not the original (very cheap) multiport adapter into the machine and connected it via an HDMI cable to an external monitor. As a result, I was using it for about five minutes and turned it off due to the fact that It was wildly lagging.

From the consequences: the Touchbar fell off partially - it was not possible to configure through the standard procedure in the settings (I fixed it myself through the terminal) + began to work much slower noticeably - visually, the performance dropped much - my 2016 MBP will perform about the same as this from 2020. I tried to make a full reset through the recovery, but it is bricked. Hopefully, I got help from an authorized center of Apple and they changed the system board and the Touch ID. Everything is working now, but it still lags noticeably - at the time of purchase and for the first two weeks, it just flew ... Now even booting before the password takes 19 seconds and then a lot of time after inputting the password. Also, it takes a lot of time to open regular apps like Chrome, Word, PowerPoint - it is not comparable to what how it was before…

Does anyone have ideas what could be the reason for it and possible steps to make it better? I already checked it with some test as Cinebench, DriveDx, GeekBench, and DiskDrill. Not something that indicates the problems.

Would be glad to hear any possible next steps!



With the limited information we currently have, based on your description of these problems starting when you plugged in your cheapo multiport adapter and now persist without it, one possibility (albeit not highly probable) is that the adapter caused electrical damage to the USB-C controller associated with one of your ports. One failure mode for such damage is that the controller can become permanently stuck in reset cycles, which causes an interrupt storm and serializes some critical kernel resources behind the driver software which is now constantly servicing the controller resets.

This is only one scenario of many possibilities. The multiport adapter might also be a red herring and you might have a completely unrelated issue that coincidentally began at the time that your multiport adapter caused a shutdown.

We could keep thinking of more scenarios. Instead, let's start diagnosing this issue the way that we would diagnose any unexplained performance loss: By analyzing a spindump.

1. Run the following Terminal command to enable kernel symbolication: sudo nvram boot-args="keepsyms=1". Make sure to copy-paste this so that you're entering straight quotes rather than curly/“smart” quotes. (If you get a permission error, you will first need to disable System Integrity Protection. You can re-enable it after you're done with this investigation.)
2. Reboot your machine and don’t open any apps except for Terminal.
3. In Terminal, enter the following command, press Return, type in your password, but do not press Return again yet: sudo spindump -reveal -noProcessingWhileSampling
4. Perform an operation that you believe is now unreasonably slow (e.g., open Powerpoint).
5. As soon as you begin to feel the slowness, go to the Terminal window where you entered your password and press Return so that the command begins to execute. Do not do anything else on the computer while it's running, otherwise you will distort the data collection.
6. After waiting for >10 seconds to collect a sample and another minute or two to symbolicate and format, you’ll get a file in /tmp/spindump.txt that contains a stackshot of every process.
7. Upload the file to PasteBin or some equivalent place and add the link to it to your original question. We can take a look at it and come up with next steps for the investigation.