We initially tested with the Catalyst Control Center. We maxed the sliders out at 1,050mhz core and 1,500mhz memory.
The card was stable at these speeds, so we fired up Sapphire's TRIXX to see if we could push it any further.
We managed to achieve an impressive 21.4% overclock before instability would occur. The memory peaked at 1,573mhz (6.3Gbps effective) speeds before it would cause artifacting.
The substantial overclock helps to push the performance of the hardware just past the reference clocked R9 270 Direct CU II OC.