Which is better, IITD civil or IIT Dhanbad for CS?

Since you haven’t mentioned the branch you are interested in, I will assume you have no particular preference. Now, the primary factor to consider is if you value the brand of the college or the branch of your choice. Consider the following points 

• You can go for a less preferred branch at the top 5 IITs and then work hard for branch change. But this would be risky as branch change is very difficult.
• If your target is to get placed with excellent packages, then choose the CSE branch, it has the best job opportunities.
• You can also choose to work for noncore placements at the top 5 IITs. However, this will be very time-consuming as you have to manage both your noncore branch and CSE. 

The best option would be to choose IIT Dhanbad CSE. It’s true that it won’t offer the opportunities and exposure that the top 5 IITs would but for me branch is more important than the brand name of the college. So, choose according to your preferences.