Unnecessary geometric detail slows down all GPUs, of course, but it just so happens to have a much larger effect on DX11-capable AMD Radeons than it does on DX11-capable Nvidia GeForces. The Fermi architecture underlying all DX11-class GeForce GPUs dedicates more attention (and transistors) to achieving high geometry processing throughput than the competing Radeon GPU architectures. We've seen the effect quite clearly in synthetic tessellation benchmarks. Few games have shown a similar effect, simply because they don't push enough polygons to strain the Radeons' geometry processing rates. However, with all of its geometric detail, the DX11 upgraded version of Crysis 2 now manages to push that envelope. The guys at Hardware.fr found that enabling tessellation dropped the frame rates on recent Radeons by 31-38%. The competing GeForces only suffered slowdowns of 17-21%.
» Fri Sep 09, 2011 9:29 pm 
