Admission to a Ph.D. program at IIT Madras depends on a number of factors. The GATE cutoff doesn’t have much weightage in the selection process. For shortlisting, IIT Madras considers the 10th, 12th, graduation, and masters percentile along with your GATE percentile. You need to have a valid GATE score but the required score is lower compared to the M.Tech cutoff.
For selection, more emphasis is placed on your performance in the written test and interview.