Zwift runs horrible in large group eventsrnts

I cannot do a large group ride as the screen freezes up. Is there some sort of speed test or diagnostic tool to determine if this is a pc video or internet issue? Very frustrated that I can never do rides with over 1000 riders.

You can try putting your log file into Zwiftalizer to see if it shows you anything that might be the source of your problem.

Also make sure that you are running the latest version of Zwift:

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Not sure if the Zwiftalizer tells me anything. See my FPS got to 1 when the event starts which is what I saw on the screen. I am running the latest Update. Did a warm up ride prior to the event and things look ok, until the event starts. Did see network errors at this time as well. I am running zwift via wifi to router in the house. Speed test says 12.3 Mbps… So where toi look next?

PCs don’t work very well with larger events. Apple TV is rock solid for me in big events. Just the way zwift behaves.

That comparison might depend, in part, on the PC’s components.

Dave wrote a helpful guide, published here:

OK Thanks for the tip. May research AppleTV…

Mine does. It all depends on your definition of a PC. A boggo laptop with integrated graphics will always struggle, because Zwift is a 3D game. A desktop with any reasonable dedicated graphics card from about the last seven years will be just fine. Frame rate in group events comes down to CPU strength anyway, another area where laptops generally struggle by comparison.


Ok that article confirmed my suspicion that the issue is not solvable. I am a software developer and I have run into cases where apps do not scale well. So I guess I will just simply avoid the mega events.

I’ve never seen any issues w/mass start events (e.g, Fondos, Tour of Zwift, etc…) while using an iPhone 8, 2015 MacBook Pro (integrated graphics), or Apple TV 4K.

If you’re seeing network errors, then it could be local or or upstream.

Network errors have nothing to do with the issue. @Dave_ZPCMR is spot on regarding this issse.

@David_Mello9572 said he saw network errors. Depending on the extent of the network errors, it is going to affect his Zwift experience. As such, he needs to check it out.

But yes, typically low FPS is the result of inadequate CPU, RAM, or a weak graphics system/card.

As for @Dave_ZPCMR comments, he’s both right and wrong. He is right in that a boggo laptop will struggle, that CPU strength is also related to frame rate, and that PCs are fine. However, there are plenty of laptops which do not have dedicated graphics cards which work fine, even in large Zwift events. I use a 2015 MacBook Pro w/integrated graphics w/out issue.

I believe @Dave_ZPCMR means Windows laptops (there also are other topics here where users have issues/crashes with Intel integrated GPUs).

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@Lin_Alan: Can you please define “work fine” wrt “Game resolution” setting, frame rate and group rider count? Thx!

Unfortunately, Zwift does not scale well to multi-core setting: it’s performance is heavily dependent on single-core CPU performance (granted, graphics performance is another important factor - but not as one would imagine…)

… and when it maxes CPU performance, some graphics do not get rendered (I’ve seen bikes without riders…), and frame rate drops.

@David_Mello9572: Care to share you specs?

Same issue. Not a network thing for me

A MacBook Pro hardly qualifies as a boggo laptop when they cost £1,000-£4,000. :wink:


I don’t have a log file from a massive group ride to look at FPS numbers. Also, I’ve been mostly using my Apple TV 4K for Zwift, occasionally going back to the MacBook Pro or iPhone depending on circumstances (aka twin toddlers).

Anyway, I looked through the log files on my MacBook and here is a typical one. It is from a small group ride of around a dozen riders:

The FPS drops at around 25min. That is also when we enter the Titans Grove climb. Scenery and whatnot increase dramatically. In any case, even at that lower FPS, it is very usable and does not get choppy or turn into a slideshow.

NOTE: That is the default 720p setting Zwift selects for my MacBook Pro. There is a lower setting as well. Also, that is an integrated GPU chipset.

For comparison, IIRC the Apple TV 4K is capped at 30fps. I’d have to dig up the source of that, but that is what comes to mind.

Tour of Zwift is coming up. I will try to join an event and run the MacBook Pro to get the stats and post back.

edit: add link

Just rode the cat b 6pm and it crashed as I crossed the line! Came back in and it saved the ride but simply as a route around watopia not stage 1!

Is this common with lots of people this year? Do I have to ride stage 1 again?