Correct when loading items, the cache loads the textures.
But this should stop sooner or later.

The CPU goes full bore during a render, but all should slow/cool down after a render is finished.

The OP states the fans keep on running till he turns the MAC OFF.

That is why I sugested a system temperatures check to see what is happening, and when.

He can check with texture caching turned OFF in General preferences.

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