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Xref: sserve comp.unix.bsd.freebsd.misc:3295 comp.periphs.scsi:34529 Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!simtel!news.sprintlink.net!howland.reston.ans.net!nntp.crl.com!crl.crl.com!not-for-mail From: ggrant@crl.com (Gary E. Grant) Newsgroups: comp.unix.bsd.freebsd.misc,comp.periphs.scsi Subject: Re: Adaptec 1542C for $125CDN -- comments? Date: 19 Jul 1995 09:25:01 -0700 Organization: CRL Network Services (415) 705-6060 [Login: guest] Lines: 35 Message-ID: <3ujbkt$l12@crl.crl.com> References: <rrwood-2106951636420001@bpci.net3.io.org> <3t93eo$brd@anshar.shadow.net> <3ta5uj$614@panix.com> <c.p.valentine-1107951205360001@ck328571cc2.open.ac.uk> NNTP-Posting-Host: crl.com In article <c.p.valentine-1107951205360001@ck328571cc2.open.ac.uk>, Chris Valentine <c.p.valentine@open.ac.uk> wrote: >In article <3ta5uj$614@panix.com>, jbrock@panix.com (John Brock) wrote: > >> I was under the impression that the bounce buffers only cost you a few >> percent in terms of speed, but I could easily be wrong here. Can you >> give me any idea how much it would reduce the speed of the card if you >> went from, say, 16MB to 20MB? Would it still be faster than a >> non-busmastering adapter (and by how much)? > >I have a Pentium 75MHz (GiGabyte motherboard) with 32Mb RAM that boots >from one of two SCSI-2 drives connected to an Adaptec 1542-CF. So, yes it >works, but how much speed am I loosing? > >I notice that I'm getting all sorts of problems with video playback. With >Video for Windows 1.1e, sometimes a movies just won't play, sometimes the >sound jerks everytime there's HD activity. I wonder if this is being >caused by the DMA problem. This did not go away when I temporarily fitted >an IDE drive, installed DOS 6.2 and Windows 3.1 on that and booted from >it. The movies on the SCSI HDs still played naff. > >I have also noticed that my capture capacity (fps) had gone *down* in >going from 486DX-33 with 8Mb RAM to the Pentium - I wonder if this is why? > >I guess you guys would recommend getting a PCI SCSI-2 card, but the cost!! >Anyone recommend something other than Adaptec, that is also cheaper? I'm >note using any esoteric operating systems (OK, I admit, its mostly a games >machine!). A PCI SCSI-2 Card (NCR810) is about $38.00 or about 20 PoundsSterling. Is that so much? I did experiments with the NCR-810 and Adaptec 2940 and the NCR 810 is about 5% Slower than 2940. Using P90 system with same drives. A 2940 cost about $200.00US. Gary :-)