user: Question: What's the directx of the model with code name RV770 PRO and a core bigger than 650.0 MHz?
Columns: ['Model', 'Year', 'Code name', 'Fab ( nm )', 'Bus interface', 'Transistor count (Millions)', 'Memory max ( MiB )', 'Core ( MHz )', 'Memory ( MHz )', 'Type', 'Bus Width ( Bit )', 'DirectX', 'Shader Model', 'OpenGL', 'Maximum Resolution', 'IceQ4 Cooling System', 'Notes']
Types: ['text', 'text', 'text', 'real', 'text', 'real', 'text', 'real', 'text', 'text', 'real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['HIS HD4850 (512MB)', 'June 2008', 'RV770 PRO', 55.0, 'PCIe 2.0 x16', 956.0, '512', 625.0, '993 / 1986', 'GDDR3', 256.0, '10.1', '4.1', '2.0', 'Two x 2560*1600 (Dual dual-link)', 'No', 'UVD 2, PowerPlay']
SQL:

assistant: SELECT "DirectX" FROM "Table" WHERE "Code name" = 'RV770 PRO' AND "Core ( MHz )" > 650.0;