I will say in a muddy english, Back in the good days the compagny were with the will to help the old computer with deficient capacity in mmx, video instruction, then They sold specific pci card made to read the video, and dvd apps. So why this good intiative has stopped by exemple it should be really kind if Intel or AMD introduced a pci card, a pci X card with all the SSE and others instructions made since 2003. It will be so usefull for the computer made before 2004. I suppose that Intel and Amd owns the right on those instructions, thats why no independants compagny has commercialised theses applications on pci card.
but isn't what you described, a graphics card? Sure, they have a different assembly language, but you can still use things like `CUDA` and `OpenCL` to program these.
