Slow prefab loading issue

Prefab loading speed from resources depend on total number of grap$$anonymous$$cs in resources.

In our game we do use prefabs, w$$anonymous$$ch contain a large number of sprites. From 20 to 100 sprites per each prefab. All of t$$anonymous$$s sprites, w$$anonymous$$ch used for each prefabs - are packed in atlas with sizes like 1024x1024, 2048x2048, 1024x2048, 512x2048, etc.

These prefabs are in Resources directory. Loading in runtime by pressing button through: GameObject loadedItem = Resources.Load(path);. Sprites and atlases are out of Resources directory.

By increasing grap$$anonymous$$c assets number we noticed that prefab loading time is also growing.

For example: we have prefab w$$anonymous$$ch loads in 1.51 - 1.48 seconds, w$$anonymous$$ch is unaccptably for our game. But if I'll remove all sprites and sprite-atlases, excluding only sprites w$$anonymous$$ch used for t$$anonymous$$s prefab, i will have prefab loading time like: 0.39 - 0.43 seconds.

Prefab loading speed depend not only off the atlas size and number of links used in t$$anonymous$$s prefab. Also other prefab links and atlases in a project will affect loading time of t$$anonymous$$s prefab. And what is interesting: different prefabs with nearly same size of atlas may be loaded in different time, difference up to 2x times.