The registration time of GRE sub is about August-September every year, the specific date is subject to the official website, but GRE Sub can only be tested once a year, so don't miss the registration time.
Extended information:
sub exam subjects:
At present, there are eight majors in the Sub exam, namely:
1. Biology, BioChemistry, chemistry, Computer Science, Literature In English and Math.
,2, which subject you should take depends on the major you want to apply for. Please refer to the requirements and instructions of the school department you are applying for to make a decision.
3. ETS adjusted the original math test in October 21, and now the math test is called math(rescaled). Math scores before and after 11 are not comparable. For details, please look for official consultation, but it doesn't matter much.
Resources: GRE sub official website-Registration-Examination Center and Date.