To be specific CBI and IB are both different body regulated by the government. Still we can get some information about who can be better in what they do.
Here are some basic distinction between CBI and IB-
• IB is involved with information analysis, whereas CBI is primarily an investigative organisation.
• Because it is used in cases involving regular people, CBI is more well-known than IB, which is mostly unknown to the general public.
• The CBI handles financial crimes and cases of corruption, while the IB monitors the movements of suspect individuals to address the issues of terrorism and insurgency.
Both the CBI and IB are equally important and to draw out a superiority is difficult. But if you're wondering which agency has more prestige, the answer is undoubtedly IB. In the IPS hierarchy, the Director of IB is above the Director of CBI.
A DGP who is appointed as the CBI Chief holds the three-star position of CBI Director. However, the Director of IB is a four-star position, making it a special position that is only held by the Intelligence Bureau's top executive. Except for the DIB, no other IPS Officer holds a four-star status.
Hope this answer helped you.