I can only say that the correlation between scores on the GRECS and scores on the GATE is much weaker than one would expect. For example, one guy who got a 99 percent on the GATE got about a 50 percentile (730) on the GRECS, as listed in the Edulix reports infoBank.
Nothing is sufficient for the GRECS exam Even a CS professor (not from a well-ranking school) who took the test got below 80th percentile, though he would certainly have faired better if he studied more. And the students who do get 90+ percentile on the GRECS still wish they got a higher score to help get into Berkeley, CMU, etc.Is preparation for GATE sufficient for Subject GRE barring a few concepts or is it completely different from the GATE exam.
So I would put it this way: some questions on the GATE exam are more relevant than others (and one would have to judge for oneself by looking at the ETS booklets), but even those good questions are just good for practicing and cannot provide reassurance, especially since even the ETS booklets cannot provide reassurance. Be afraid, be very afraid That's the kindof attitude one needs to score well as almost everyone scores lower than they expect.