http://www.tomshardware.com/reviews/radeon-r9-290x-hawaii-review,3650.html «We’ve also come to learn that AMD changed the double-precision rate from 1/4 to 1/8 on the R9 290X, yielding a maximum .7 TFLOPS. The FirePro version of this configuration will support full-speed (1/2 rate) DP compute, giving professional users an incentive to spring for Hawaii’s professional implementation.»