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Re: [TCLUG:11032] Setting up X-Windows



>         If I'm not mistaken, a lot of video cards have dual ported
> internal RAM busses so that refresh has no effect on bus access by other
> parts of the card.

I haven't heard this touted much these days. Most cards use plain EDO or
SDRAM these days, which far as I know aren't dual ported. 

Now that I think of it, where I read about this was in the XFree
documentation somewhere, back in the days of 486s and Tseng ET4000w/p's.
There was a performance tip about how the acceleration engine got
whatever bus time is left over from the RAMDAC, so if you ran the
dotclock too close to the limits of the vram bandwidth, the acceleration
engine would be choked and unable to work its magic...

Have things changed since then? I suppose some benchmarks are in
order...

>         Anybody been with PCs for long enough to remember the CGA snow
> problem?  :-)

Thats because bus priority was given to the CPU, not the ramdac... Silly
IBM.