Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_25839957_5 (core_clock___mhz__ VARCHAR, memory_bandwidth___gb_s__ VARCHAR)

### Question ###
What core clocks ( mhz ) have a 21.3 memory bandwidth ( gb/s )?

### Accurate SQL ###

SELECT core_clock___mhz__ FROM table_25839957_5 WHERE memory_bandwidth___gb_s__ = "21.3"