Dear student,

Let me clear you that, if you want to take admission in top IIT's, NIT's and IIIT's through GATE Exam , then your score must be very good in the GATE exam. For admission into top IITs,  you must score a GATE rank below 200. However, the students having a rank in the range of 600-800 can also get admission into IITs and IIITs. For admission into leading NITs, the students should score a GATE rank in 350-800 range.

You can also check the previous year cut-offs for IIT's, NIT's to get an evaluation about admission with rank.

Hope it helps.