Table schema:
CREATE TABLE table_19161046_1 (directx VARCHAR, code_name VARCHAR, core___mhz__ VARCHAR)

Question: What's the directx of the model with code name RV770 PRO and a core bigger than 650.0 MHz?
SQL: SELECT directx FROM table_19161046_1 WHERE code_name = "RV770 PRO" AND core___mhz__ > 650.0