The Apple A9X / PowerVR Series 7XT GPU is an integrated graphics card in the Apple A9X SoC which can be found in the 2015 Apple iPad Pro. At the End of 2015 it is one of the fastest GPU in ARM based tablets (next to the Nvidia Tegra X1).
According to Chipworks, the GPU offers 12 shader clusters (384 ALUs) and therefore twice as many as the A9 (6 clusters, 192 ALUs) in the iPhone 6S. Currently there is no marketing name for the 12 shader version and it seems to be a custom variant for Apple. It is manufactured in 14/16 nm (3D transistors) at TSMC and Samsung (according to rumors).
The performance of the GPU is very good and in GFXBench the results are even better than a current GeForce 940M laptop graphics card. However, the direct comparisons of different platforms should only give a rough indication on the speed. Thanks to the Metal API, the iPad is able to use the graphics hardware very efficiently.