Ah yes, an example of what I am seeing:

   
Marks-MacBook-Pro.local (172.16.0.239)                                                                                                                                                                                         2020-10-29T14:28:27+0200
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                                                                                                                                                                                               Packets               Pings
 Host                                                                                                                                                                                                        Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. 172.16.0.254                                                                                                                                                                                              0.8%   126    3.9  34.7   2.5 232.1  54.9

Mark.
On 10/29/20 14:07, Mark Tinka wrote:
Hi all.

I've been on High Sierra for several years now due to a limitation with an app that couldn't deal with Apple's latest rounds of system permissions since Mojave. Eventually, I gave up on waiting for them to fix it and upgraded my older Butterfly keyboard laptop to Catalina 4 weeks ago.

At the same time, I picked up the new Magic keyboard laptop 2 weeks ago which came with Catalina.

Over the past week, I've been troubleshooting a massive jitter issue on Catalina, just between itself and my home router. For control, I have a Windows PC (tower-top) using a wireless adapter to connect to my home network. That has no jitter at all.

I have noticed as much as 300ms+ jitter on Catalina.

I then asked a few friends around the world to run tests for me on their own Catalina installations to their local router over wi-fi, and the results are the same. Jitter so high that what should be a 1ms - 5ms latency can (for a short period) jump to 200ms+, 300ms+, 400ms+.

On the off-chance that it is an issue with the new wireless chips on the later MacBook models, one of my friends tested the same on a 2013 MacBook Pro running a beta version of Big Sur. Same story!

Another friend in South East Asia, testing on a 2018 13-inch MacBook Pro running Catalina, also had the same issue.

A Google search suggests that this is some known issue since Mojave, to do with Location Services, and some other apps, in a non-deterministic way:

    https://apple.stackexchange.com/questions/263638/macbook-pro-experiencing-ping-spikes-to-local-router

For me, even after disabling all or some Location Services features, the problem remains.

Is anyone else seeing this on their Catalina Mac's while on wi-fi? If so, does anyone know what's going on here?

Ideally, this wouldn't matter if it was just a cosmetic issue - but I do actually see physical impact to performance of network access to/from the laptop, which has all the hallmarks of high jitter and/or packet loss.

An app like Zoom, which can display network performance data for a session in real-time, does indicate nominal packet loss for audio and video on this device, while other devices on the same WLAN are happy.

Thoughts?

Mark.