> Correct me if I'm wrong, but isn't Altivec just a fancy name for the maths processor in the MPU? If so, then Altivec is to PPC what the 68881 FPU was to the 68000.
If we're talking about the time when the x86 didn't have any real FP support, yes. As in MMX, no.
Altivec is basicly a way of introducing math paralellism. It's useless for speeding up most Photoshop type of tasks, but invaluable for FFT, Fractals, or software synthesizers (as in music). If you want to modify a buffer or a stream, without reading data from additional buffers or streams, then it's great. If not, then it's useless.
Let me clarify that. A software synthesizer crunches numbers like no other software. It takes a single input stream, like f.ex. a looped soundwave and modify it using variables that rarely change. One sample in. one sample out and many, many DSP-like operations inbetween.
Most people do not realize what kind of performance the simulation of a classic analog synth require. Playing a piece of music using a software synth pretty much demand all that a modern CPU can deliver. The Altivec changes that.