Unreal Engine
Like the competing ATI Rage Pro, RIVA 128 was never able to accelerate the popular Unreal Engine in Direct3D mode due to missing hardware features. It was, however, possible to use the engine's OpenGL renderer, but unfortunately OpenGL support was quite slow and buggy in the original Unreal Engine. Performance in Quake III Arena, a game using an engine more advanced than Unreal Engine 1, was better due to the engine having been designed for OpenGL.