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Date:      Tue, 11 Feb 2003 21:54:15 +0100 (CET)
From:      Marco Beishuizen <marco@beishuizen.info>
To:        Andrew Gallatin <gallatin@cs.duke.edu>
Cc:        FreeBSD alpha mailing list <alpha@FreeBSD.ORG>
Subject:   Re: Why is XFree86 on FreeBSD/Alpha much slower?
Message-ID:  <Pine.BSF.4.53.0302112147000.294@tsunami.bsd>
In-Reply-To: <15945.24538.794799.926276@grasshopper.cs.duke.edu>
References:  <Pine.BSF.4.53.0302112042190.294@tsunami.bsd> <15945.23721.759825.313603@grasshopper.cs.duke.edu> <Pine.BSF.4.53.0302112129370.294@tsunami.bsd> <15945.24538.794799.926276@grasshopper.cs.duke.edu>

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On Tue, 11 Feb 2003, the wise Andrew Gallatin spoke, and said:

>
> Marco Beishuizen writes:
>  > On Tue, 11 Feb 2003, the wise Andrew Gallatin spoke, and said:
>  >
>  > >
>  > > Marco Beishuizen writes:
>  > >  >
>  > >  > Hi,
>  > >  >
>  > >  > I have two machines, one Intel (450mhz) and one Alpha (600mhz). Both are
>  > >  > running FreeBSD 4.7-RELEASE and WindowMaker as windowmanager. The Intel
>  > >  > has a Matrox G400max and the Alpha has a Matrox G450.
>  > >
>  > > What kind of alpha?  What sort of slot is graphics board in on the
>  > > alpha?  On the pc?
>  > >
>  > > Drew
>  >
>  > The alpha is a PWS600au, it has a 21164 cpu. The Matrox sits in one 32
>  > bits PCI slot. The Intel is a PIII/450, and the G400 sits in the AGP slot.
>  >
>
> OK, so the AGP slot probably has at least 500MB/sec DMA.
>
> But: All 32-bit slots on your alpha sit behind a pci-pci bridge chip,
> connecting to a main bus whose DMA characteristics are similar to:
>
> DMA rate for 8192 Byte pages (32bit / 33MHz bus)
> Timing 32 pages.
>         bus_read  (send) = 73 MBytes/s
>         bus_write (recv) = 129 MBytes/s
>
>
> The PCI-PCI bridge slows this down even further.  You might try
> setting the magic SRM console variable to allow putting the card
> into the 64-bit slot (see the alpha hardware notes that Wilo
> maintains).   But it will still suck moderatly.
>
> FWIW, the AGP Permedia board in my UP1000 doesn't suck.
>
> Drew

I always thought that graphics performance was the strengh of the Alpha.
But it seems to be the opposite.

It's a lot slower than the Intel, but I don't think that it sucks so
much that I should buy another graphics board. I guess I'll have to live
with it.

Marco
-- 
"What are you doing?"

"Examining the world's major religions.  I'm looking for something
that's light on morals, has lots of holidays, and with a short
initiation period."

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