Original sentence: As this is layered over DirectX.The Mobility Radeon series claims full OpenGL 2.0 support, however, under Microsoft's Vista Operating System the OpenGL driver (known as an Intsallable Client Driver, ICD) is not supplied.This version of OpenGL is layered on top of DirectX making a performance drop
Edited sentence: AMD/ATI does not mention this is fact in their technical overviews, or features lists.As this is layered over DirectX, the performance is nothing short of awful.Instead they claim full OpenGL 2.0 support.OpenGL applications under Vista are forced to use Microsoft's implementation of OpenGL, version 1.4.OpenGL support has never been delivered to the marketplace.The Mobility series claims full OpenGL 2.0 support, however, under Microsoft's Vista Operating System the OpenGL driver (known as an ICD) is not supplied.The drivers provided for the Mobility Radeon series are functionally limited under Vista.This version of OpenGL is layered on top of DirectX making it painfully slow