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Xref: sserve comp.unix.pc-clone.32bit:764 comp.unix.sysv386:26411 comp.unix.bsd:9097 comp.os.linux:19665 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!yale.edu!ira.uka.de!math.fu-berlin.de!informatik.tu-muenchen.de!roell From: roell@informatik.tu-muenchen.de (Thomas Roell) Subject: Re: ET4000/W32 and VESA VL-Bus In-Reply-To: thomas@aeon.in-berlin.de's message of Tue, 15 Dec 1992 19:08:25 GMT References: <BzBEI1.CH@aeon.in-berlin.de> Sender: news@Informatik.TU-Muenchen.DE (USENET Newssystem) Organization: Inst. fuer Informatik, Technische Univ. Muenchen, Germany Date: Thu, 17 Dec 1992 08:06:53 GMT Message-ID: <1992Dec17.080653.4328@Informatik.TU-Muenchen.DE> Lines: 40 >does anyone already using the new ET4000/W32 chip, perhaps in an >VESA VL local bus version? How is the performance compared with >ET4000AX and does it work with XFree86 1.1? I think nobody actually uses the ET4000/W32 currently, since I don't know any SHIPPING hardware yet. I do assume that the ET4000/W32 is much faster than the ET4000, based upon some expiriance I had with other DRAM based accelerators. Take for example the WD90C31 (DS24X). If you use the SVGA only driver you'll get around 9000 xstones, if you use a driver that uses the internal acceleration capablities, you'll get around 45000. It would assume that the latter number is the lower limit for the ET4000/W32s performance. But there are some constraints you should think of: a) The performance of a DRAM based accellerator depends VERY much upon the refresh frequency (i.e. dot-clock). Let's say you have a DRAM bandwidth of 100MB/sec (let's assume it doesn't matter wether these are RAS/CAS or RAS/multiple-CAS cycles). If you use a 1024x768 60Hz resolution, you need about 65MB/sec for screen refresh only. This leaves you with around 35MB/sec for doing graphics. If you use 1024x768 72Hz, you need 75MB/sec for screen refresh. That means you have only 25MB/sec for doing graphics. If you consider that you can use the fast page mode accesses for screen refresh only and most of the graphics operation won't be able to use them (since they are interruped by screen refresh cycles), this computation is in fact over optimisitic. b) The ET4000/W32 was build for MS-Windows. Hence I do expect that they haven't all in the chip that you would like for X. On the other hand I do expect too many things tuned for MS-Windows to you have to work hard to get X-Windows semantics. - 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 ...