Question: What's the directx of the model with code name RV770 PRO and a core bigger than 650.0 MHz?
Schema: create table table_19161046_1 (directx varchar, code_name varchar, core___mhz__ varchar, PRIMARY KEY (directx))
SQL: select directx from table_19161046_1 where code_name = "rv770 pro" and core___mhz__ > 650.0