To make it easier to reliably compare images, please either attach them separately (see attachments here), or put them in some kind of slider like this:
1 -
https://corona-renderer.com/comparer/qNDZ082 -
https://corona-renderer.com/comparer/qA6bKR One major difference I can see is that one image is darker than the other. Other than that, they are very similar in terms of noise and quality.
The difference might be caused by:
- different tone mapping
- different secondary GI cache calculation
Another thing is that the clouds have a different pattern, and they affect environment lighting, so this can explain the difference in brightness. I suspect the scene setup between the two platforms is not identical.
Also, we would need to know a bit more about your tests, for example: Which exact version of Corona for 3ds Max and for C4D did you use? What is your CPU model? Were you doing some additional tasks in the background while rendering? (for example browsing the internet) Are your CPU temperatures within the acceptable range so that there is no throttling?
And lastly (and maybe the most importantly), rendering for just a bit over a minute does not give us a good understanding of real rendering performance. Using a pass limit (for example 100 passes) and then comparing the render times to reach this number of passes would be more accurate.
I think the "OMG" is not really applicable here. :)