Issue with too much ram occupation on ios devices

I created a blank scene without any script and removed all packages, then i added a box with a material assigned to containing four 10mb textures(resolution: 4k -compression: normal) , then i made a Webgl1 build with brotli compression with .wasm format. (build size:28 mb)
An ios device with 1GB ram stuck on 90% while loading (which means there's not enough allocated ram!)
while memory allocation limit on this device is 645mb.
how is it possible that such a small project decompressed and heap size exceed 645 megabytes ?!



this is the Editor log :

Code (log):

1. Build Report
2. Uncompressed usage by category (Percentages based on user generated assets only):
3. Textures               42.7 mb     75.9%
4. Meshes                 0.0 kb     0.0%
5. Animations             0.0 kb     0.0%
6. Sounds                 0.0 kb     0.0%
7. Shaders                151.9 kb     0.3%
8. Other Assets           5.7 kb     0.0%
9. Levels                 10.5 kb     0.0%
10. Scripts                270.5 kb     0.5%
11. Included DLLs          13.2 mb     23.3%
12. File headers           8.0 kb     0.0%
13. Total User Assets      56.3 mb     100.0%
14. Complete build size    85.4 mb
15. Used Assets and files from the Resources folder, sorted by uncompressed size:
16. 10.7 mb     12.3% Assets/test size/4.jpg
17. 10.7 mb     12.3% Assets/test size/3.jpg
18. 10.7 mb     12.3% Assets/test size/2.jpg
19. 10.7 mb     12.3% Assets/test size/1.jpg
20. 153.2 kb     0.2% Resources/unity_builtin_extra
21. 0.9 kb     Assets/test size/New Material.mat
22. 4.1 kb     0.0% C:/Program Files/Unity 2019.1.4f1/Unity/Editor/Data/UnityExtensions/Unity/GUISystem/UnityEngine.UI.dll
23. 4.1 kb     0.0% C:/Program Files/Unity 2019.1.4f1/Unity/Editor/Data/UnityExtensions/Unity/GUISystem/Standalone/UnityEngine.UI.dll
24. 0.9 kb     0.0% C:/Program Files/Unity 2019.1.4f1/Unity/Editor/Data/UnityExtensions/Unity/TestRunner/UnityEngine.TestRunner.dll
25.  

 

After a long research, there are memory consumptions I know:
1. WebAssembly code compiled size. If you have 30M uncompressed code size, It would eat-up 150M more or less
2. Heap, depends on your game content and logic. Typically maybe 64M~256M
3. Cavas, depends on resolution
4. Textures, only support DXT compressed texture. On mobile, it will eat-up 4x memory more than desktop browser.
5. Audio, WebGL build seams to heave some problem. Audio uses much more memory than apps.
6. JS Memory, interact between C# and JS or some other allocation in JS.

If you sum them up, It would be much larger than you think.

 

Those 4k textures are going to be loaded uncompressed on iOS Safari, at 67MB each. That's 268MB only for textures.

Also, the allocation limit for a browser tab is lower than for an app.

 

Yep.On iPhone 6s/7/8, safari mem limitation is 1G, while app is 1.3G more or less.