Attached is the scene I got from a customer for debugging of an unrelated problem. I cannot show more due to the implied confidentiality, but it is a typical production scene. There is probably something set up incorrectly in 3ds Max, but the difference still shocked me - rendering phase is 25 times faster.
This is the behavior I was observing in 3dsmax - the max bitmap is consistently 10-15% slower, but in some very specific cases the difference is MUCH bigger for some reason. This is the case where woodoo debugging such as resaving to .gif helps, but nobody was able to discover a reliable pattern.
PS: If you are going to repost this to vray forum, please ask vlado what T-shirt size is he ;)