Teccie question - help please!

Hi, I have some kind of technical issue going on.

The images here show Zwift on my tablet and the image on the TV, taken within a few seconds of each other – I’m wondering why sometimes the TV goes all pixelated like this.

The incoming Wi-Fi speed on my range extender at the time was 30+ mbps and I cast the image from the tablet to the TV using Chromecast. Everything (the tablet, TV, Chromecast and Wifi range extender) is less than ten feet/three metres apart.

The TV is usually ok, but this sometimes does happen – I think mostly at weekends, but I couldn’t swear to that.

Any ideas as to why this is happening?

All help appreciated, thanks!

It seems like some sort of Chromecast-related issue. Which model of Chromecast do you have? Amd what tablet?

Has this only just started happening, or has it been doing this for a while?

Thanks for coming back, Steve.

The Chromecast isn’t marked in any way, but it is an older model - certainly not the latest 3rd generation.

The tablet is a Samsung Galaxy Tab S2 running Android 7.0.

The issue has been going on for a while, but it only happens occasionally. Most of the time it’s fine. As mentioned, I do associate the problem with the weekend, but I’m not absolutely sure of that as I’ve not noted exactly when it’s been happening.

Here’s an article showkng the various generations of Chromecast - What generation Chromecast do I have

Could it be at the weekend that you have other people in the house using your wifi more, e.g. watching movies? Your tablet is having to send the video image constantly to the Chromecast for it to display it, so it’s more the wifi in your house that’s the issue here as opposed to the internet outside your house.

Another thing is that at the weekend, you may have more riders on Zwift, so your tablet is having to do more work in rendering the nearby riders, and at the same time it’s having to stream the video to the Chromecast. And that’s not the most powerful tablet in the world.

Aah, couldn’t see the tiny writing! It’s a 2nd generation, NC2-6A5.

No other people around at the weekend (courtesy of lockdown…) and the 30+ mbps was at the point of delivery inside the house rather than outside (measured using Ookla on my phone next to the tablet).

I’ll keep an eye on the numbers Zwifting - I have seen upwards of 40,000 on occasion, but haven’t cross checked that with any instances of the pixelated image.

Thanks again Steve for coming back to me, much appreciated.



It sounds like your wifi is probably ok, unless the times that it goes pixellated happens to coincide with your router choking or similar (very difficult to measure, of course).

Yes, do keep an eye on how busy things are in your ride when it happens. Could be your tablet struggling with a busy ride and having to stream to the Chromecast at the same time. Or it could be that the Chromecast itself is sometimes struggling to keep up.

Thanks again Steve,

The joys of technology, eh? I’ll do my best to isolate/identify the source of the problem and let you know if I succeed.


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Are you sure it’s a Galaxy Tab S2?

Zwift to my knowledge doesn’t run on this.

Works fine


@Phil_S6 Just my two cents worth - I have a couple of the 1st and 2nd gen units. They have only ever sporadic performance when casting or watching content (Red Bull TV for eg) and I have never been able to get consistent high quality despite a clean network. Doesnt bother me too much as I use them mostly for music these days but if I was needing to cast more often, I’d find a non-Google solution.

Just realised you’ve an S2 and not a 2 which is archaic.

I’m with the others, suspect it’s the Chromecast just not being fully up to the task.

Thanks to all for comments and suggestions, I’m going to try another casting solution. Phil