Vladimir Dergachev
On Sun, 20 Dec 1998, Mike A. Harris wrote:
> On Thu, 17 Dec 1998, Jon M. Taylor wrote:
>
> >> > It probably can't even be used as fast swap. I suggested such an
> >> >idea in the old GGI FAQ, and someone later told me that the VRAM+memory
> >> >controller logic on standard video cards is designed around the assumption
> >> >that writing to video memory will happen much, much more often than reading
> >> >from video memory. I don't remember the particulars, but the upshot is that
> >> >bandwith reading from VRAM is maybe 1/4 of bandwidth writing to VRAM. As
> >> >such, VRAM reads will be so much slower than VRAM writes that any gains you
> >> >might have gotten from the extra RAM evaporate. If you have "normal" VRAM
> >> >I/O and maybe accels and DMA too (i.e. something is actually using the video
> >> >card for its intended purpose) going on simultaneously the situation gets
> >> >even worse.
> >>
> >> Are you saying that swap to VRAM would be slower than swap to
> >> hard disk?
> >
> > No. I am saying that you'd better not be wanting to do any
> >serious video work with the video card if you do use it for swap. And
> >normal system [S]DRAM is cheaper and sits on a faster bus with no
> >contention from other I/O devices.
>
> The presumption is that someone has a 3dfx card with RAM on it,
> that is *NOT* being used for video, and that as such there is
> wasted resources in the machine. Thus using those resources is
> definitely going to be better than not using them assuming that
> there are no technical reasons why it can't be used as such.
>
>
>
> > AGP and/or UDMA architectures will
> >render this idea obsolete anyway.
>
> I don't understand how. Will hard disks become faster than video
> memory? If so, why not put a hard disk on the video card. It
> makes 0 sense.
>
>
> --
> Mike A. Harris - Computer Consultant - Linux advocate
>
> Linux software galore: http://freshmeat.net
>
>
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