Zwift on PC graphics stutter last two days

I am new to Zwift, maybe 3 weeks or so including the free week. It’s run just fine all this time, I ride every day, working on level 11, so it’s not like I haven’t used it much. The last two days the graphics stutter to distraction. Even at the map while selecting a ride it stutters while drawing the route!! The PC is a desktop, Core i5, 8GB Ram, Windows 10 Pro, Nvidia GTX 660 with 2 GB. The PC is dedicated to the trainer. Nothing has changed. I have rebooted, uninstalled Zwift and reinstalled, updated graphics driver. The PC is on wired gigabit Ethernet, so no network issue. Working Ant+ dongle. I have a first gen Kicker, all that, power, speed, cadence, hr, work fine, just the stuttering.

If an iPad or phone will run Zwift, how can I have problems with graphics on a desktop PC?

I saw the three or four old thread regarding this, but no real solution there.

OH, and the CPU is running 30-35% and the GPU ~50% when Zwift is running,

Hi Tom.

Big groups can put a heavy load on the pc. The good news is you have a nice setup, if you can get a used gtx960 you will see huge improvements, for cheap.

I had stuttering graphics during a group ride yesterday (<400 riders). I’ve got a 27" iMac. We were riding in Richmond. This is the first time I’ve ridden Richmond since they refreshed it.

The only other time I’ve had this issue recently was the start of the Griepel ALS ride and I chalk that up to the >6,500 riders who participated.

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Well, I have another PC with WAY more horsepower in the graphics department, maybe I’ll try that one.

IF I’m going to be buying any graphics cards, it’ll be a 1060 or something. I’d go $100 pretty easily!!!

No big groups, I was sitting alone at the spawn point both times, with 2 or 3 riders going by. AND, there were no big groups near by and only ~2500 rides total both times. I start riding and jerk, jerk, jerk, every second or so, very annoying.

It just really seems like it should run fine on my setup, and DID for three weeks every day, there’s the rub. Even with some huge groups blowing by me a hundred strong!!!


Put you log file in

Hmmmm. never heard of that. May be too late, I setup another PC, this a Core I7 with a GTX970. If this one doesn’t run it, I’m outta here!! I’ll fire up the other PC and try the zwiftalizer thing just for grins. Always willing to learn something.

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I’m new to Zwift too and I noticed this on Wednesday and Thursday last week but it seems to be ok again today.

Hmmm… I’ve been on zwift for over two years now on the same machine and over the last week or so have experienced some serious stutters. Basically the screen will stutter and freeze for about 0.5 - 2 sec, and my avatar will draw with parts missing (eg the body geometry) but then eventually everything catches up and carries on as normal. I noticed it occasionally (but not always) with the ‘ticker tape’ sprint/kom congrats and can also happen when passing a few riders.

Strange, I understand it can slow with loads of riders etc but these recent stutters are way worse than I’ve ever seen and with no obvious reason. I actually started thinking my graphics card may be on its way out but if other folks are experiencing something similar I thought it worth a mention.

I’ve had no problem since switching to a more powerful PC with a more powerful graphics card, but who knows. The times it happened with me there was no excessive “traffic” or graphics happening, just a fairly steady stutter, very brief, all the time and as I mentioned even on the map screen while selecting a ride it stuttered drawing the route on the map!!

Have the same issue for the last 2 weeks now, running zwift for years with a MSI QE70 2QD Apache game laptop; Intel I7, Windows 10, Nvidia GTX950M, full graphics, never had a issue with stuttering. My first troubleshooting was the internet connection, hooked up to Lan with cable instead of Wi-Fi. Didn’t make any difference. Also on quite roads the issue is there.

Same here (legacy i5, W10, GTX1050Ti), seems to occur quite reliably around intersections and sections with hairpin turns.

Down to 30 fps in a couple of sections in today’s ToW race with only 9 other riders in the event. it’s getting rather distracting. I used to get 60 fps consistently (1080p60 display so no need to go above that) with just an occasional drop to ~55. Will next try reverting to an earlier version of the GPU driver just for the heck of it (started noticing these first after an upgrade).

Out of curiosity, how do we see frame rate while riding? Or are your seeing if after the fact in Zwiftalyzer or something?

Earlier I have just used Zwiftalizer, but since this started bothering me, I have enabled the live fps display while riding, see for details.

Am I imagining things, or did this get better in today’s update?

Stutter is not always caused by a GPU or graphics related issue, for something to suddenly occur like this, having worked fine in the past, 2 things could of happened:

  1. An update - a buggy one at that which caused various problems.
  2. Back end issues, if the servers can not get packets out to users fast enough, you will stutter as the game is attempting to work with out the data it needs and awaiting packets (TCP vs UDP)

If it now suddenly works, then they found the issue and it was backend problems.

Yeah, my current hypothesis is that it is not directly GPU-related and has something to do with nearby rider positions and an overloaded backend. Earlier issues around intersections are now much less noticeable, but on the other hand events in Watopia on extremely busy days still got the stutter even though only a handful of other riders were visible overall.

That being said, it doesn’t have to mean the solution can’t be GPU-related. Finally got around to playing with the GPU settings, turned on adaptive sync (even though my display doesn’t really support it) and 30–40 fps looked fine in a large group ride yesterday. (I mean, 30 fps has been enough for the movies for a century, so it shouldn’t have to look that bad…)


@Anna_Ronkainen the difference between movies and games is movies using a blurring effect between frames, thus you do not see the stutter, where as games and the like you do not have this option (some games do allow it) so you notice every little frame drop. Zwift, like video games, what you do not want is large drops to min FPS, if you keep a steady 40FPS, that is better and smoother than 70 FPS, dropping to 38FPS, to 49FPS, down to 32FPS and such.

The more consistent you can keep your FPS, the smoother the experience when your below 60 or so FPS. When you start getting up into higher FPS, things just become butter smooooth!