I rendered the following to images using a GTX1050TI with only 4GB of VRAM (not the best card for this). One of these images took me 45mins using standard settings, no denoising. The other image only took me 5 mins using denoising. There's is ABSOLUTELY a HUGE difference! You cannot tell the difference between the two at all, yet the denoised version was MUCH MUCH faster without any quality loss. This is especially important on a low end video card like mine as you cannot denoise at all when you run out of VRAM and that makes renders MUCH MUCH slower without denoising on low end cards (or any card for that matter)...
Now which of these images was 5min and denoised, and which one took 45 mins? Look close, you may be surprised at the answer...
A:
View attachment 1689570
B:
View attachment 1689571
Picture A was rendered in 5mins and denoised. You can tell when you zoom in that image A has lost some quality compared to Picture B (it's blurrier and has lost some details). Without zooming in, however, you are correct in that they are almost identical and certainly acceptable for posting here.
EDIT - I was mistaken! Picture B is actually 45 mins. So, as Night Hacker says, it really is hard to tell sometimes when something is denoised or not lol!
I appreciate your trying to help me out. I am actually using denoiser for now, but I personally think it's better to not use it if possible. And the only way to not use it is to have better hardware. I actually have a powerful desktop that I use for video editing and even started on Blender work. BUT, it has an AMD card (as a long time NVIDIA guy, I wanted to try out the competition), and unfortunately AMD GPUs are not compatible at all with Daz. Ugh.
So, all of my Daz rendering is currently being done on my laptop - which has a GTX 1070.
Currently, I do cut off renders when they reach around 90% progress, and then put it through the intel denoiser. It does depend on the scene, since some scenes are obviously way more complex and thus take longer. But there
is a loss of quality when denoising because, as
m4dsk1llz said, it is a destructive process. Even if it might not be noticeable at first glance. Though I think how noticeable it might be does depend on the actual model/scene/lighting too.