Unexpectedly poor frame rate performance on recent game updates (PC)

This relates to desktop Windows PCs with an Intel CPU and discrete Nvidia graphics card. I can’t comment on crashing, other platforms or anything else that may also be going on. I’m putting this here because it’s clearly not being noticed in the game update threads, of which I’ve posted in two.

Zwift has always been CPU bound when there are a lot of other riders around; the frame rate tanks, with the GPU not being fully utilised. This is an unfortunate but fundamental and expected feature of how Zwift works and I’m doubtful we’ll ever get away from it. It happens to everyone, with how far the frame rate drops being dependent on how fast/strong the CPU is. When it’s not busy though, even very slow/old CPUs have always been fine for 60fps or more (the exception being Makuri Islands). In almost all solo rides, the game allowed the GPU to max out if necessary. However in the last two updates this basic behaviour has changed. I can only just max out a GTX 1050 Ti in perfect conditions (4K with vsync disabled, offline and zoomed in overhead); because otherwise the CPU is holding it back.

Until Jan 2022
Solo rides: GPU bound
Busy areas/group rides/Pace Partners: CPU bound
Makuri Islands: Mostly CPU bound even with nobody else around (for no apparent reason)

Since Jan 2022
All rides, all worlds, irrespective of rider density: CPU bound

I’m raising this because it’s a clear and obviously detrimental change to how Zwift behaves as a piece of software. It’s ruining the experience on systems that have previously always been capable of providing a rock solid 60fps unless the number of other riders nearby is high or the GPU cannot give any more. Some areas are very noticeably hit, such as the main straight on Richmond where simply changing the camera angle can invoke/revoke a massive performance penalty. I’ve observed this penalty being almost 30% on my main Zwift PC (170fps to 120fps). That’s bad enough, but on a budget system with lower end CPU you go from a reliable and constant 60fps to well below it. In that same spot on Richmond I was getting 47fps. Merely looking towards Titans Grove can see the frame rate drop hugely (75fps to 58fps) even when you can’t physically see it. The GPU isn’t rendering stuff you can’t see, but it feels like the CPU is still calculating for them. I’m sure some people will claim these frame rates are fine (below 60fps is… not okay) but my point is that this is massively inferior to how it was before, and how it’s been for literally years and years. All the time I’ve been aware of the platform at least.

If I had to guess, I would say that changes appear to have been made to how far into the distance the client ‘sees’ in terms of things it needs to compute on the CPU. The camera pointing down a long, busy road, or over towards an area full of assets/shadows, seems to be causing a massive amount of extra CPU load that wasn’t there before. Or maybe it used to be based on a proximity circle around the camera, and now it’s a cone going off into the distance and so it changes based on where you’re looking. Either way, the GPU is very often choked and the frame rate is lower than expected, like you’re in a group ride even when you’re not.

I really hope this is a bug or error that can be addressed as soon as possible. However if it’s a choice - say the rest of the game has been brought into line with Makuri Islands - then it seriously needs a rethink because it’s really damaging the experience for PC users and making the hardware requirements incredibly high compared to ever before.

Happy to provide log files and any other details that may help. Thanks.

Just adding my voice to get this focused on as my Zwift only rig is also impacted.

Appreciate the time you invest in this space Dave, would be nice if Zwift also acknowledged this.

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Hi @Dave_ZPCMR

Thanks for sharing all those details and I’ve raised your concerns to a higher technical authority on the team. I’m hoping to get a response soon and I’ll let you know when I have more information.

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Thanks, I look forward to hearing more. As mentioned elsewhere I’ve put together a lot of dedicated Zwift PCs at this point so I spent ages trying to understand why performance is suddenly inferior when I’m not doing anything different. As such I’ve tested and seen this behaviour on several different systems and configurations. Even sold one graphics card assuming it was faulty (having switched out every other component) because the frame rate was so unexpectedly low. Got another, better card, exactly the same… :confused:

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Today I was seeing sub 25fps on approach to the Tempus Fugit banner (AMD 3900x and 3080rtx).
After a minute or so it returned to the still low but normal 70-90 fps.

This happened every time over a 2 hour ride.

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Solo ride? I think the Tempus Fugit thing is a different bug (also happens in a few other spots from time to time), but if you weren’t in a group then 70-90fps is really quite poor for a 3080, which would be because of the issue mentioned in the OP and your CPU holding it back which didn’t used to happen solo. I’d expect much more than that solo on Watopia with your GPU, and I believe you have a very high refresh rate monitor so it should be maxing out unless you have the frame rate capped.

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It was solo yes.
Zwifts CPU bound performance issues are a separate issue to the bug reported here tho.
I can live with the relatively low fps on a £1000 GPU.
The drops to 25fps for extended periods and constant “hiccups/frame stickies” had me alt-tabbing out of Zwift today. Just not a pleasant experience atm.

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Some videos here, since I know they are usually considered useful.

https://streamja.com/6Ko2N
https://streamja.com/q5X1k
https://streamja.com/n3y3M
https://streamja.com/BOJM3

In none of them is the GPU maxing out, nor are there lots of riders around, so there’s no reason for the frame rate to be dropping just by looking a certain way.

I have revived a few old PCs recently and tried zwift out on them.

I have an old windows tablet
1.2GHz Intel Core M 5Y71 processor (dual-core, 4MB cache, up to 2.9GHz with turbo boost)
8GB ram

appreciate it is a bit old and not exactly going to break any records for specs but it used to be fine, I rode Innsbruck recently and it was pretty much unusable.

I have also tried a couple of old 4th gen i5 PCs and they seem ok but probably because my FPS is very low anyway so i wouldn’t notice “bad” when it happens!

One thing I have noticed which i’m not sure if it is related is that there are a lot more riders weaving around on the road - i used to think this was people with wifi issues and the game redrawing their position a lot but seems to be happening a lot more these days than it ever used to.

Any fix incoming? Right now I’m riding with a pace partner at 9fps on the above high-spec machine.

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That sounds like a different (and far more significant!) problem tbh.

Fan viewing you at 80fps here. :wink:

Edit:

Skip to 3 minutes for the Tempus Fugit banner issue.

And no, it’s not an issue my end. The system is fully tuned for high fps gaming.

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Definitely not right. It’s a totally different issue to what this thread is about, though.

30-40fps in the Coco group is about expected with your CPU. 10fps clearly is not.

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It’s actually far lower fps than it was a few months ago and nowhere near expected for what is still a pretty fast CPU.

One example - I always spawn at Road To Sky. Before the recent updates, I’d see 100-120fps with a few riders at that spawn. Now I only get ~70fps. Nothing has changed on my end.

Yeah that sounds like the extra CPU load I’m talking about. :+1:

What I meant was that the frame rate with a busy Coco will always tank on a 3900X (Zen 2 isn’t particularly good at Zwift), and the 10fps thing is clearly a separate bug, because that should never happen either way.

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Same here, I don’t know what happened in the latest updates but now I’m getting 10 fps average in a large event, it’s no longer usable. I’m on a i7-6700HQ CPU @ 2.60GHz, 24 GB Ram, GTX 970M. Never had this problem before, but I didn’t train too much lately so I’m not sure when it appeared.

@Steven_D Hi Steven,

I wonder if you could provide any update at all on this?

Thank you

@O_ne_Eyed_Jack

Last I heard from the higher ups on the team was that they were waiting to see if we’re still getting reports of these these frame rate issues since the last few Zwift app updates.

Regarding this issue, yours is the first post on this thread I’ve seen in about 2 weeks, so maybe things have improved? Hard to say.

That sort of implies 2 things. Either something was changed that they hope has improved things or they are hoping the issue goes away on its own.

In recent days I’ve seen situations where looking down a long straight stretch of road (in London) resulted in reduced frame rates and then as I got closer to the end of the stretch, things improved back to the usual 60 fps, only to have them tank again as I did the 180 degree turn and had a long look down the road again. So for me, I would say the situation hasn’t improved.

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