1d iv or 5mk3 noise wise?

Hi..i have 5d mk2 and 1d mk3

most of the time im using 1d and loving it for its built and speed but when it comes to low light places i just cant bring my 1d its too much noise... so im considering to sell my 1d mk3 and getting an mk iv

i have try looking at canon sample of 1d iv images but a real live experience from users who have 1d mk3 and iv is better than just a picture

so please tell me is it better to get 1dmk iv or 5dmk 3 as their price at this point is pretty close