Flooring Tile - cement board or mud base for 24inch marble

i am building a new house, and plan on placing 24x24x3/4 inch creme marfil marbile on the entire first floor, about 3300 square feet, i have been told by some that cement board with a thin mudset is ok, and others have wanted to pour a thick mud base, which is better, any thoughts, thanks

That's a lot of weight on that floor, unless it's on a slab. Be very certain the floor is built strong enough to support it without flexing or neither will work well. Concrete board, installed correctly, will do the job, but nothing beats a good mud set if the installer knows what he's doing.

thanks, my builder tells me that the subfloor is very strong, and firm, and both tile guys who have come out to bid have agreed, the difference is, that one is pushing a mud base, which he does, the other is pushing cement board, thanks
newbld

How strong is strong? You need to have a deflection rating of L/720, 2x what would be required by code if you want to install stone. Joist size? Joist spacing? Joist span? You will need a full mud set, not a scratch coat to keep 24" stones level butyou are also talking upwards of and extra 10 lbs/sf so the 720 rating should be calculated using 20/40 loading, not 10/40 loading as is normally figured. You need to hear this from your arch or an engineer, not some guy who jumps on the floor and says it seems fine and strong.