Yeah, most of my renders are with Genesis 8 characters. It just so happens this is a Genesis 3, but I set the mesh resolution to 3 or 4 for rendering, so it's still pretty good. I do all my renders at 1920x1080 though, so if you use a higher resolution than you will probably want more iterations. But yeah, they all render within 5 mins or less on average.
Just for fun, I done that same shower scene with no desnoising, 100% setting at a quality of 2 just for extra stress and this was the result... the water drops are sharper and there's a slight lighting difference on the floor... it took me over 2 hours to render at 1080P... it is SLIGHTLY better (I see no difference on Sophia herself though)... to me that is just not worth waiting 2 hours. I will go up to 10 mins at a higher set of iterations if I have a higher resolution. Keep raising the iterations, maybe try 1000. It will take longer, but it won't take 3 hours. Probably 10 mins at most, depending on your video card.
I done A LOT of experiments. Basically rendered at 100, 200, 400, 800, 1600 iterations etc... or whatever set of values you want to test then compare images and when you no longer see a difference worth waiting for, use that value. Everyone's different, I used to use 200 all the time, then doubled it to 400 and lately I have been doing 800, but still drop to 400 for simple scenes sometimes as I don't see much of a difference (not enough to wait long periods for anyhow) but we're all different.
I don't feel this render is significantly improved to warrant over two hours.
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