Driver efficiency has improved considerably for both Direct3D and OpenGL.
Numerous D3D games show 2-3% gains at low resolution.
The small batch size tests in 3DMark05 show improvements as large as 15% on some products.
In OpenGL, several game titles show improvements in the lower settings.
Wolfenstein - Enemy Territory, for instance, shows gains as large as 15% in low resolution (driver-bound) cases.
Doom III performance improves 5-10% at low settings.
Call of Duty improves 5-6%.
Half-Life 2 performance also improves as much as 20% over Catalyst 4.11 in certain sections of the game.