I’m using Zwift (1.79) on a Windows 11 PC with an ethernet fibre internet connection. Lately I have noticed that whenever I have the Zwift app running my internet connection becomes very slow.
I have measured my internet speed using Fing and normally it looks like this:
However, when Zwift is running it looks like this:
Does anyone have any idea about why this happens and what I can do to solve it?
That’s pretty strange. Zwift shouldn’t consume a lot of bandwidth. It’s usually possible to run it on a cellular connection as long as signal is OK.
Yes, and it doesn’t even look like Zwift is using much bandwidth at all and Zwift’s own connection is really stable.
CPU exhaustion can also affect the system’s ability to handle network interface activity. You could check that as well. Because Zwift is heavily dependent on a single CPU core, you need to understand whether a single core is being maxed out even if the CPU has a lot of unused capacity on other cores (which would be normal for Zwift).
Yes, it looks like one core is at 100% running the Zwift process. What can I do about that?
The problem seems to be local, only affecting the PC Zwift is running on. Other devices on the same router seem to be unaffected.
The first thing I would do is upload a log file to zwiftalizer.com so you see how the game is performing, then I would go to the Search tab in zwiftalizer and look for other systems with the same CPU and GPU to compare their performance and some of the game settings that are visible in those results. That might tell you whether everyone with your hardware is experiencing similar performance.
I would check whether you have the correct device drivers for whatever network connection you are using on your PC. There’s something wrong if one core being maxed out throttles your net throughput so badly.
I have found the solution! It was the Lenovo Vantage app that caused it. It has a “network boost” feature that automatically limits internet bandtwith for other apps when running a game. I disabled the feature and now internet speed is back to normal.
It’s refreshing to see a post with the actual solution.
All too often, someone will come back and say something like, “I figured it out.” without offering details.
Thank you.
