From: Kenn Humborg (kenn at domain bluetree.ie)
Date: Thu 20 May 1999 - 15:57:22 IST
Paul Jakma wrote:
> my argument is that refresh rate is a constant totally dependant on the
> capabilities of the RAMDAC, and totally decoupled from RAM. And that the
> speed of the RAM is only of influence on keeping the graphics engine
> saturated.
>
> whether your ram is fast or slow is only relevant to the graphics engine. If
> the ram is too slow, then the graphics engine stalls - but the RAMDAC will
> still output an image at X refresh rate, it'll just be the same image as on
> the previous scan.
No it won't. The RAM we're talking about here is the chunk
that stores the pixels to be displayed. This is 'output' from
the graphics (aka rendering) engine (if there is one), not input
to it.
The RAMDAC does _not_ contain the whole image. It still has
to get the pixel data from the main RAM. If the image data was
stored in the RAMDAC, you'd have to upgrade the RAMDAC to get
higher resolution*colour_depth values.
AFAIK, some cards use the 'spare' space in the video RAM for
acceleration purposes (and for textures and stuff on 3D cards).
Kenn
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