Memory use profiler: 300MB, Webpage inspector: 2.8 GB!?

Additional in-browser memory profilers that are useful:
- In Firefox, open the Unity page, and then in a background tab, navigate to about:memory and do a snapshot there.
- In both Chrome and Firefox, you can snapshot the JavaScript heap to get a breakdown of where memory is used in detail.

If the tools give cryptic looking results, try pasting a screenshot here (or link to a build) - I can see if I can decipher it for you.

 

That 494 MB is taken up by the WebAssembly heap, i.e. basically the Unity engine code. Note that it is just a memory reservation, not all of that memory is necessarily in use. You can gauge the amount in actual use by dividing the Unity profiler usage by the total heap size, e.g. 281.8MB / 494 MB = 57%.

You can preallocate the heap to a specific size by applying an Editor script with a statement like

PlayerSettings.WebGL.memorySize = 320; /*megabytes*/

That will help do a "tighter" reservation that might not overcommit as much.

However the 2.8GB memory usage from your first post reads like something completely different - WebAssembly heap has a max size of about 2GB, so you may be looking for some other source here.

 

Also your screenshot is in the Simple view. Try doing a snapshot in Detailed view, and also look at the Memory Profiler package, at https://docs.unity3d.com/Packages/com.unity.memoryprofiler@0.1/manual/index.html . That can give a more detailed view inside memory that is resident in WebAssembly heap.