>      However parallel processors are "hobby" projects all over
> the world. It would be nice to have 2.25 million processors in
> parallel so each could render its own pixel. On a PII 333MHz
> (128M, Win98, POV 3.1) machine only the most complex internal
> reflection scenes (a "city of glass" for example) fall below 24
> pixels per second. If we had 2.25 million processors, each could
> render its assigned pixel 24 times a second resulting in the
> required 24 frames per second.

The problem with multiple processors is that n number of x-MHz
processors aren't as fast as 1 x*n-MHz processor. I.E. they don't run at
full capacity. Two processors is a huge performance gain, four is too,
eight is ok, sixteen gets a little, thirty-two or more would be a huge
waste of money. The thing is, the graph of performance vs. processors
starts to level off after so many, because multi-processor machines
waste a lot of time with processor communication. With 1024 processors,
each processor has to "talk" to 1023 others, and there is minimal gain
over 512 or 256. You may could instead use 1024 seperate motherboards
each running a copy of POV. That would be plausible, because you would
only need the video card, monitor, CD, etc on the main system, which is
half the cost of a computer. And with the POV ability to render a
selected section of the picture, you could indeed have real-time
rendering. However, 2000000 PII's with motherboards would cost a good
billion and a half dollars, which is probably less than multiple Cray
XMPs though I really have no idea what those cost.

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