*BSD News Article 9340


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From: mike@starburst.umd.edu (Michael F. Santangelo)
Newsgroups: comp.unix.pc-clone.32bit,comp.unix.bsd,comp.os.linux
Subject: Re: ET4000/W32 and VESA VL-Bus
Date: 28 Dec 1992 02:27:58 GMT
Organization: University of Maryland, Chesapeake Biological Laboratory
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Message-ID: <1hloneINNfnn@cbl.umd.edu>
References: <BzBEI1.CH@aeon.in-berlin.de> <1992Dec17.080653.4328@Informatik.TU-Muenchen.DE> 	<1992Dec17.190542.2662@utagraph.uta.edu> <1992Dec18.095906.3950@Informatik.TU-Muenchen.DE>
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>Yes, you are right, partially. Of course the serious graphics boards
>use all VRAM, which are dual ported RAMs specifically for graphics
>boards. They have a internal shift register for the screen refresh
>data and a random access port for the graphics engine. And of course
>those allow you to use the 100MB/sec (which was again just a sample
>number which seems to be realistic for the WD90C31) exclusively for
>the drawing operations. But the point was that somebody asked about
>the ET4000/W32, which is a DRAM based (and not VRAM based) solution.
>In my eyes, nothing justifies the usage of DRAMs for a graphics board if
>you want to use it for a GUI. The price difference is rather minor
>in those days.

>Also there are quite a number of S3 chips, which use EITHER VRAM or
>DRAM:

>	86C911		VRAM
>	86C924		VRAM
>	86C801		DRAM
>	86C805		DRAM
>	86C928		VRAM


>What I am saying is that for 1028x768 in 70Hz and 1280x1024 you should
>generally forget the DRAM based solutions. Even if they look good at
>benchmarks; most of these benchmarks used a 640x480 resolution,
>where the screen refresh only takes 25MB/sec, and the available
>bandwidth for graphics operations is quite the same as for VRAM based
>solutions. But if you use the DRAM based boards at 1024x768, 70Hz,
>you'll see the difference.

>- Thomas

January '93 BYTE magazine did a review of higher performance SVGA
graphics accelerator boards (p.202-206).  The Orchid Fahrenheit VA
which uses the 86C801 board did quite respectably in their tests
(which were performaned on all the boards at 1024x768 resolution, 72Hz).
The Actix Systems GraphicsEngine 32 also used the S3 based 86C801 and
had even higher scores.  Yet according to your chart they can
only use DRAM.  Again the tests in BYTE were ay 72Hz.  Comment?


--
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Michael F. Santangelo                 + Internet: mike@cbl.umd.edu      [work]
Computer & Network Systems Head       +           mike@kavishar.umd.edu [home]
Univ MD: CEES / CBL (Solomons Island) + BITNET:   MIKE@UMUC  [fwd to mike@cbl]