Performance issues - compiled UE4

Why compiled Development Editor (which according to docs is “Release”) from UE4 source is way way slower than released one from launcher? I’m talking big difference here.

I compiled 4.13.1 from GitHub.

P.S. I’ve seen others having the same problem.

P.P.S. Question is not about compilation time, but how slow compiled-from-source editor works compared to downloaded one from launcher.

Hey SoulSharer,

Do you mean the time it takes to compile the engine when getting the source code?

When you download the engine from the launcher, it is already built and the “source” code is there for reference. This means that when you create a game project with the binary (launcher) version of the engine, it is quicker because the engine is already built. Whereas when you use the source code from GitHub, you have to build the engine yourself, which does take time (between 30 and 90 minutes). Once the engine is built, it should be much quicker.

Can you describe what you are saying in more detail?

Thanks.

Hello, thanks for a quick answer. What I mean is compiled version works slow compared to compiled official version (downloaded from launcher). Not talking about compilation taking long, it is no brainer. Thanks. :slight_smile:

I am still not sure what you mean. Can you give an example?

Thanks

Hey SoulSharer,

Thanks for the report. What you are seeing is a consequence of the difference between using the binary version and the source version. The source version generally has more to do when the project is launching compared to the binary version. While the difference is noticeable, it is also expected and therefore, not a bug.

My recommendation is that if you do not need to make source code changes, go ahead and use the binary (launcher) version of the engine. However, if you do need to alter engine code, the longer loading and compile times will be a part of it.

Compiled from source

  1. Cloned Unreal Engine from GitHub
  2. Compiled engine (4.13.1 in
    Development Editor configuration)
  3. Opened game project
  4. Waited for shaders and game code
    to compile
  5. Closed editor after asset
    compilation

From that point on opening game project takes 5-10 minutes, even though everything is compiled. Dedicated server when ran through editor takes long to spin up too. I’m talking 2-5 minutes here.

Downloaded from launcher

  1. Takes about 1-2 minutes after asset
    compilation to open project
  2. Dedicated server starts up fast, takes at most 1-2 minutes

Why that much difference in performance, does Unreal Engine that goes public (via launcher) compiled differently? Maybe there are more optimization, different compiler or something else?
Thanks.

You can fiddle with what modules you’re using or whats being included into the project but source takes longer to compile and launch. It’s how it works.

Out of curiosity, what bug in 4.13.1 prevents you from using the binary version?

Unfortunately we can’t use binary version because there is a bug in 4.13.1 that will be fixed only in 4.14 and we need source version for adding new features later on.

Do you have any suggestion on how to minimize that difference between source and binary versions? It will be much appreciated, because it is a big concern when whole team experiences such slowdown.

Do we have to disable some modules, fiddle with compilation via compiler flags or maybe something else?

Thanks!

I tried to disable all modules we don’t use, no use, still the same I’m afraid.
Here it is, though someone was first to make pull request https://github.com/EpicGames/UnrealEngine/pull/2874

I found out how to build UE4 from source to be as fast as binary version provided with launcher, so for reference I’ll post here.
It takes several steps:

  1. Compile AutomationTool
  2. Go to {ROOT}\Engine\Binaries\DotNET
    and type “cmd” in address, then
    click enter OR run cmd and cd into
    that directory
  3. Now type in AutomationTool
    BuildGraph -target=“Make Installed
    Build Win64”
    -set:HostPlatformOnly=true -script=Engine/Build/InstalledEngineBuild.xml
    -clean
  4. Click enter and wait till you see
    that build succeeded
  5. Enjoy your UE4 binary build in
    {ROOT}\LocalBuilds

Reference:
https://docs.unrealengine.com/latest/INT/Programming/Development/InstalledBuildReference/index.html