http://www.realworldtech.com/pag ... 70510142143&p=1
The truth is that there is no technical reason for PhysX to be using x87 code. PhysX uses x87 because Ageia and now Nvidia want it that way. Nvidia already has PhysX running on consoles using the AltiVec extensions for PPC, which are very similar to SSE. It would probably take about a day or two to get PhysX to emit modern packed SSE2 code, and several weeks for compatibility testing. In fact for backwards compatibility, PhysX could select at install time whether to use an SSE2 version or an x87 version – just in case the elusive gamer with a Pentium Overdrive decides to try it.
But both Ageia and Nvidia use PhysX to highlight the advantages of their hardware over the CPU for physics calculations.
In Nvidia’s case, they are also using PhysX to differentiate with AMD’s GPUs. The sole purpose of PhysX is a competitive differentiator to make Nvidia’s hardware look good and sell more GPUs. Part of that is making sure that Nvidia GPUs looks a lot better than the CPU, since that is what they claim in their marketing. Using x87 definitely makes the GPU look better, since the CPU will perform worse than if the code were properly generated to use packed SSE instructions.
