Good day together,
As a general information at the start: when I use the word "normal" for describing my WiFi connection behavior, it means that the WiFi connection is showing high latency spikes, between normal latencies. It's just "normal" for me after several months with the Mac mini.
Today I did the following tests:
- Only one monitor connected via USB-C to DP
- Connect a second monitor via USB-C to DP
- Connect a third monitor via HDMI
- Disconnect the third monitor via HDMI
Results:
- Normal behavior. High latency spikes, but nothing special.
- As soon as I connected the second monitor, I had complete packet loss to the gateway in the same subnet for round about 7 pings. I then attached the grounding and the WiFi connection went back to normal. Detaching the grounding made no difference any longer.
- As soon as I connected the third monitor, I had again complete packet loss to the gateway in the same subnet for round about 15 pings. I then attached the grounding and the WiFi connection went back to "normal". Detaching the grounding made a visible difference regarding the WiFi latency.
Interesting behavior in between: While I had 3 monitors connected, I attached the grounding over both USB-C to DP cables to the Mac mini. This produced complete packet loss to the gateway in the same subnet as long as the grounding was attached that way. This behavior was reproducible in that moment.
4. Detaching the third monitor connected via HDMI made a little difference in the latency. But, at all, the WiFi connection went back to "normal" again.
This is showing me again that there is something totally wrong in the design of the Mac mini. At least, this is my opinion. Unfortunately, it will/would be hard to explain this to Apple, because you will never get in touch with an Apple engineer who would understand what was done by myself or in this forum regarding the WiFi behavior of the Mac mini.
At the moment, I am still in contact with the Apple engineers (via telephone) to exchange debug data (Wireshark captures, WiFi diagnostics,...) for the third time, to prove that there is something wrong with the Mac mini and not with my environment/my WiFi setup. During the phone calls, I am always getting the feeling they are assuming that the behavior is caused by my WiFi setup and not by their Apple device. Even though a great number of other devices (Apple and Windows devices) in the same WiFi do not have any problems. But maybe that is only my experience with the Apple support. ...please excuse the little frustrated complaint about my Apple support experience.
Kind regards
Dominik
PS: I hope my English is understandable. I am a native German speaker. ;-)