That is not true, even the 384 Shader on the A12-9700p 15W TDP is way faster than 15W TDP HD620. Go to Notebookcheck and compare 15W A12-9700p to HD620 like the Core i7 7500U.
When Bristol Ridge is not CPU limited at low resolutions the AMD iGPU is a lot faster than HD620.
Bristol Ridge throttles like mad at 15 W in actual titles, that's why it ends up slower than the 620.