No, qualifying GATE is not mandatory for admission to M.Tech programs at VIT Vellore if you qualify for VITMEE.

VITMEE (Vellore Institute of Technology Master's Entrance Examination): This is the institute's own entrance exam for M.Tech programs. Qualifying VITMEE is your gateway to admission, and you have already done well by qualifying with a score of 4.

GATE (Graduate Aptitude Test in Engineering): While not mandatory, a good GATE score can be beneficial. It might:

• Earn you scholarships or fee waivers.
• Increase your weightage during the selection process for some programs.
  
  https://www.careers360.com/university/vellore-institute-of-technology-vellore
  
  I hope it helps!