Return to BSD News archive
Received: by minnie.vk1xwt.ampr.org with NNTP id AA5139 ; Tue, 22 Dec 92 04:01:17 EST Xref: sserve comp.unix.pc-clone.32bit:782 comp.unix.sysv386:26438 comp.unix.bsd:9144 comp.os.linux:19816 Newsgroups: comp.unix.pc-clone.32bit,comp.unix.sysv386,comp.unix.bsd,comp.os.linux Path: sserve!manuel.anu.edu.au!munnari.oz.au!spool.mu.edu!umn.edu!csus.edu!netcom.com!hasty From: hasty@netcom.com (Amancio Hasty Jr) Subject: Re: ET4000/W32 and VESA VL-Bus Message-ID: <1992Dec18.185612.10836@netcom.com> Organization: Netcom Online Communications Services (408-241-9760 login: guest) References: <1992Dec17.080653.4328@Informatik.TU-Muenchen.DE> <1992Dec17.190542.2662@utagraph.uta.edu> <1992Dec18.095906.3950@Informatik.TU-Muenchen.DE> Date: Fri, 18 Dec 1992 18:56:12 GMT Lines: 63 In article <1992Dec18.095906.3950@Informatik.TU-Muenchen.DE> roell@informatik.tu-muenchen.de (Thomas Roell) writes: >>I thought that since EGA boards have been using double ported DRAM to >>avoid this? Or are you saying 100MBs is for both ports? I have noticed >>some ads saying their S3 board uses double ported DRAM so are we to >>assume that most are not? If so then as you say this will instantly >>destroy any speed a coprocessor can give as the only thing that matters >>then is faster DRAM. I am no expert (as is obvius to the experts by >>now) but I am just trying to get this picture. If ram access has always >>got this refresh overhead (assuming a single port) then any board will >>simply be limited by DRAM bandwidth. > >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, All XS3 published benchmarks are run at 1024x768 clocked at higher than 60 Hz. I obtained the results from netters because I don't own a high resolution monitor. During candid, e-mail exchange I do state my own benchmarks. In the future I will state the clock frequency and the resolution. Amancio Hasty >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 > >-- >------------------------------------------------------------------------------- >Das Reh springt hoch, e-mail: roell@sgcs.com >das Reh springt weit, #include <sys/pizza.h> >was soll es tun, es hat ja Zeit ... -- Amancio Hasty | Home: (415) 495-3046 | ftp-site depository of all my work: e-mail hasty@netcom.com | sunvis.rtpnc.epa.gov:/pub/386bsd/incoming