We contacted Nvidia over it, and received the following answer from Lars Weinand, Technical Marketing Manager at Nvidia EMEA:AMD's Radeon HD 7000 "Southern Islands" GPU series is fully compliant with DirectX 11.1 (except the rebranded products from the 6000 family).
"The GTX 680 supports DirectX 11.1 with hardware feature level 11_0, including all optional features. This includes a number of features useful for game developers such as:
Partial constant buffer updates Logic operations in the Output Merger 16bpp rendering UAV-only rendering Partial clears Large constant buffers
We did not enable four non-gaming features in Hardware in Kepler (for 11_1):
Target-Independent Rasterization (2D rendering only) 16xMSAA Rasterization (2D rendering only) Orthogonal Line Rendering Mode UAV in non-pixel-shader stages
So basically, we do support 11.1 features with 11_0 feature level through the DirectX 11.1 API. We do not support feature level 11_1. This is a bit confusing, due to Microsoft naming. So we do support 11.1 from a feature level for gaming related features."
NVIDIA Kepler not fully compliant with DirectX 11.1
Posted on Thursday, Nov 22 2012 @ 13:41 CET by Thomas De Maesschalck