if you're looking to do big scene renders in a shorter time, then i'd highly suggest using an optimizer. It was the only way i could do a bigger render before i got my gpu a couple weeks ago. Lighting is also a huge drain on resources. Limiting the amount of lights in a scene/hdri (and making them brighter) will lower the time taken to get good results.
For reference, even with a decent gpu (2070 Super), there's too many lights with too many dark spots to get decent results from this scene without an excessive amount of rendering time.
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