Pixomatic wasn't just on par with UE1's SW rasterizer it was somewhat explicitly designed to be the SW rasterizer for UE2. The thing was notable by the fact that it had feature parity with HW Direct3D implementations of the time and worked by dynamically compiling D3D shaders into x86 code (which had the interesting feature that it used ESP as general purpose register).
IIRC the idea behing Intel's Larabee at least partly involved running pixomatic on that hardware.
I think the Havok engine ran on that on software mode too, at least for the first Max Payne. I remember forgetting to install NV drivers back in the day, and the game launched smoothly at 640x480 with no issues. Ok, it was uber-grainy, but still playable.
IIRC the idea behing Intel's Larabee at least partly involved running pixomatic on that hardware.