Catastrophe definition, a sudden and widespread disaster: the catastrophe of war. See more.
1 Total Time: The computer-delivered GRE takes 3 hours and 45 minutes for the average student.  Experts recommend sitting for the GRE exam one year prior to entering graduate school. This allows for ample study time and the option to retake it if desired.
5. GMAT is an 800 marks test, wherein you need to score more than 750 for the top universities and colleges. On the other hand, according to the new format, GRE is only a 340 marks test, where a score of more than 330 would book your slot in one of the top universities.. Duration of the test. GMAT is a fixed 3.5 hours test with a fixed number of questions, while GRE is minimum 3 hours, and can go up to 4 hours depending on the current format.