i wish to pursue a PhD from the US sometime in future. i dont have any immediate plans as i am still in my 1st year M.tech. but i am worried that if i dont give my GRE now,the changed exam format might be a problem.what shoukld i do?

It wont be a problem. The new exam is designed to measure the same skills as the old. Also, if you take the exam now and do well, it is a good backup to have. Start early if you plan to apply for PhD. The process is long and requires a lot of upfront research. PlanetGPA.com

You can take the exam right now. Your score is valid for 5 years. Universities consider scores which are 2-3 years old. If you are planning to apply within 2-3 years, you can take the GRE now and apply with the score you get now at the time of admission. Hope my answer has solved your query. If it