There's been discussion about shaders before, so you may want to look
into the archives over this.  However, I'll reiterate one of the
points.

OGA1 will be reasonably fast.  Not powerful, but fast.  Even though
it'll run at a relatively slow clock rate.  Why?  Parallelism.  The
fixed-function pipeline has the benefits of any pipeline--every pixel
will take nominally one cycle to process.  If there are 100 stages
required to process a pixel, then you can have 100 pixels in flight,
each one taking one cycle to process.

Now, imagine reimplementing that serially in a programmable shader.
Now, those 100 steps have to be done one after another.  So each pixel
now takes 100 cycles to process.

This is probably an exaggeration.  But it explains why shader-based
GPUs have to run at 500MHz or more.
_______________________________________________
Open-graphics mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-graphics
List service provided by Duskglow Consulting, LLC (www.duskglow.com)

Reply via email to