UpdateUILayouts creating massive amounts lag (110-130FPS to 30-40FPS on High-End Laptop)

When I was on my game ([NPC GUNNERS] Starlit Isles - Roblox), I noticed that UpdateUILayouts was taking up a bunch of resources on my Microprofiler which brought my ~110-130FPS down to ~30-40FPS.

Microprofiler Dump: microprofile-20240601-203956.html - Google Drive


I am curious; Is this issue relating to any update of UI list layouts such as if something dynamically scales the canvas of the frame?

If so, an experience of mine also seems to be experiencing massive server lag when LoadCharacter has to make a copy of my ScreenGui, which does indeed contain UI list layouts. I wonder if the two are somehow correlated.

Hi @9vvo - thank you for the heads up and for providing the microprofiler dump!

As best as you can, could you provide repro steps that produces this behavior in your game? Does it happen 100% of the time? Do you know if its happening on other platforms?

If you’re able to isolate the issue and share a place file with us, that would be extremely helpful, but we also understand that could be a time consuming process, so no worries if its not possible.

Thank you!

This happens when a Player-Owned Ship or Train moves (but usually player-owned trains). It happens about 30-50% of the time and I haven’t checked if it affects other platforms

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Another thing, where should I send the file?

So turns out there were several Enabled BillboardGuis parented to a Package within ReplicatedStorage which I found to be the culprit behind the lag. Putting this here if anyone else has a similar issue in the future.

tldr disable any billboardguis if they’re in a package/model parented to replicatedstorage if you’re having this issue

Hey @9vvo thank you for providing those additional details! If still have a repro file around, feel free to DM it to me and we can have an engineer take a look. It sounds like this could be a bug, or some unintended interaction with BillboardGui and packages.

Hi @9vvo, I’m taking a look at the repro file you sent in. Would it be possible to provide more detail about when this slowdown occurs? Does this happen in studio edit mode, or only during a specific part of gameplay?

This issue happened all the time while I had billboardguis enabled inside a package in ReplicatedStorage