Daz 4.9.3 iray issue when compared to Daz 4.9.2

Black Snow Princess

I seem to have an issue when rendering one of my old scenes. The resulting image from Daz 4.9.3 seems to be much more grainy than the image in Daz 4.9.2. I have attached a few images of the shoulder of the character which seems to be particulary grainy. The glove of my character also appears to have strange marks on it. One cause for the glove problem is that some materials have opacity to 0. I can solve this issue by delete the unused geometry in the glove; however, I figured I would post as the problems may be correlated.

The Daz 4.9.3 images was rendered for 8 hours while the Daz 4.9.2 images was rendered in 2 hours, so I do not believe, this is a quality problem. In the Daz 4.9.3 the environment appears to be reflecting more light while the character seems to be reflecting less. So, I tried increasing the lighting by 10x. The scene was much brighter but the shoulder was still grainy. Because the character, glove, and environment noticeably changed, I believe the issue may be related to the surface materials. Therefore, I rendered a few tests of the different skin materials of Natsuko (which is the skin of my character), Genesis 3, and Victoria 7. The Natsuko skin looks more grainy especially around the neck/jaw area.

Does anyone know what change could have occured with the new Iray that would cause this graininess and how to fix it?

unglobetrotteur_7cfbf208b8

Indeed. I am new to Daz and just did a few portrait rendering and I see a lot of noise. I assume I was doing something wrong but maybe not.