Re: is there a buffer?

Ao (bogart@mailroom.com)
Sun, 10 Sep 2000 19:33:29 -0500


> I tried switching the BIOS setting and it didn't change anything; in fact
it
> almost seemed to make things worse.
>
> It also doesn't seem to make any sense. If I switch to KDE I don't have
these
> problems, and KDE to me almost seems like a much bigger, bulkier desktop
> manager. I have an 8 MB video card, plus a Voodoo Card (I don't know if
it's
> even being used or not), so video memory should not be an issue for me;
> nevertheless I seem to have problems.
>
>
> John Gruenenfelder wrote:
> >
> > The reasoning I've heard is bus saturation.  You move a large window so
the
> > video card must transfer a lot of data.  For 1024x768x32 that's about
3.1MB
> > for a full screen update, which happens many times as you drag the
window.
> >
> > Most modern video cards have an option for bus mastering.  This is
usually on
> > by default.  What this means is that when the video card is transferring
all
> > of that data, it takes complete control of the bus until the transfer is
> > done.  This is hand because it results it better performance for your
video
> > card.  Because of this, giving your music player a larger buffer won't
help
> > because that data still has to travel over the bus where the bottleneck
is.
> >
> > To fix this you can:
> > 1) work in a lower color depth resulting in less data.
> > 2) turn off bus mastering.  Usually in your BIOS there is an option to
"Assign
> >    IRQ to VGA".  Turning that off should disable bus mastering.  If not,
there
> >    should be an X server option.  Of course, this will reduce the
performance
> >    of your video card.

    Well, I've always thought that this issue was related to CPU/RAM clock
speed.  On my old p120 w/96MB RAM I had this problem frequently.  After I
upgraded the machine to Athlon 550 w/128MB RAM I never had it happen again.
    Are any of you running machines <=200Mhz? Just a thought.

Ao

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