Re: SecondSight FPS

[philip@labtam.oz.au (Philip Stephens)]

Matt Portune writes:

>Ok, so assuming the application has extremely well-written code, and is 
>designed to push the SS to it's max... Theoretically, how fast could the 
>card go?

  Assuming a 3Mb transfer rate, this leads to the following maximum frame
rates, assuming you're trying to redraw the entire screen every frame:

  320x200x256 mode (~64K of data per frame): 50 fps
  640x200x256 mode (~128K): 24.5 fps
  640x400x256 mode (~256K): 12 fps
  
  and so on.  If you use the VGA controller to do read-modifier-write cycles,
you can apparently get up to 5Mb transfer rate, which will boost the above
frame rates further.

  However, keep in mind these are absolute maximums...you're not just going
to be pushing pixels around, you're going to be doing other things.  But the
above rates would be fairly accurate for, say, scrolling the screen (as an
example of one kind of full-screen operation).

=========== Philip Stephens, Systems Programmer, Labtam Australia ============
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