Apple Catalina Appears to Introduce Massive Jitter

Thu Oct 29 12:27:31 UTC 2020

Is it actually jitter or is it potentially the wireless network card going into sleep mode? I have seen that type of behavior on Apple products when the cards go into low power mode although I can’t say I have noticed that on my laptop.

> On Oct 29, 2020, at 8:11 AM, Mark Tinka <mark.tinka at seacom.com> 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.
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