CREATE TABLE table_28157 ("Graphics" CLOB, "Launch" FLOAT, "Market" CLOB, "CPU" CLOB, "Code name" CLOB, "Device ID" FLOAT, "Core clock  (  MHz  ) " CLOB, "Execution units" FLOAT, "Shader model" CLOB, "DirectX" CLOB, "OpenGL" CLOB, "OpenCL" CLOB, "Memory bandwidth  (  GB/s  ) " CLOB, "DVMT  (  MB  ) " FLOAT, "CVT HD" CLOB, "QSV" CLOB)

What core clocks ( mhz ) have a 21.3 memory bandwidth ( gb/s )?
SELECT "Core clock ( MHz )" FROM table_28157 WHERE "Memory bandwidth ( GB/s )" = '21.3'
SELECT "Core clock ( MHz )" FROM "table_28157" WHERE "Memory bandwidth ( GB/s )" = '21.3'