Why unity 2020.1 become so slow?

From other task of windows 10, getting back to unity take so long than before,

entering game mode take more long, overall stops occurs very frequently.

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If you don’t really need it, switch to release mode if it isn’t already set up (the bug icon at the bottom right)

I am already in Release mode. (I didn’t changed, it seems default)

Even preview packages and if Uinty / project are not on an SSD can have a negative impact on performance. During the beta phase I also had the problem that after an update of a package the first play lasted a very long time. But that has improved, especially after I moved my project to an SSD. At the moment I have no problems switching to Unity from another task, unless I changed scripts before and Unity is compiling, I’m in Debug mode, it was default after project upgrade.

me too
i’m using 2 versions of unity, 2020.1 and 2019.3.
i can record screen smoothly with 2019 version but it’s very laggy in 2020 version, it’s only below 20 FPS, sometimes it gets crash which never happen in unity 2019


ACTIVATE THIS! I HAVE NO IDEA WHY IT’S NOT DEFAULT! IT’S BALZING FAST WITH IT!

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It’s not default as 95% of projects are incompatible with that.

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I agree entering play mode since the new update in 2020 and I think 2019.3 was when it began

Bro this saved me… Don’t have to wait 10 seconds each time anymore but its instant… Love you man…

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Don’t get too excited. Enabling this option sometimes does not call every of your event on the play. If you checked the below 2 options it will be the same as the default.

Hell yeah!

I couldn’t for the life of me understand why Unity reimports everything when I hit play, even though everything’s already reimported after I modified my code.

Thanks to your post I reached this page which I recommend to read - it tells you why this is done
But it is still SUPER useful to disable this, it makes things SO much faster :smile:

Thanks again!

Interesting. Can someone explain what exactly does it do?

It skips reloading domain and scenes. There are caveats if you do it, but play mode does become almost as fast as it used to be in Unity 4.x, although with caveats.

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Thank you for the response!

Removing a package takes on average 2 minutes, it’s a real nightmare.

Agreed. I never use the Package Mangler for removing packages. I close Unity, edit the Packages/manifest.json directly, remove the lines and reopen Unity.

If I screw something up, revert in source control and retry.

Also: Unity installs lots of extra unwanted packages in new projects (collab, testing, rider and other junk):

https://forum.unity.com/threads/temp-unityengine-testrunner-dll-error.1133938/#post-7287748

The only effect when you are not using these is to massively slow you down and potentially cause errors.

About the fastest way I have found to make a project and avoid all this noise is to create the project, then as soon as you see the files appear, FORCE-STOP (hard-kill) Unity (with the Activity Manager or Task Manager), then go hand-edit the Packages/manifest.json file as outlined in the above post, then reopen Unity.

Sometimes the package system gets borked from all this unnecessary churn and requires the package cache to be cleared:

https://stackoverflow.com/questions/53145919/unity3d-package-cache-errors/69779122

Yep, it’s quite an endeavor to start out with a empty project these days, makes me laugh when I remember Joachim’s comment on the 500ms response threshold.