From owner-freebsd-hardware Mon Mar 25 13:52:24 1996 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id NAA09044 for hardware-outgoing; Mon, 25 Mar 1996 13:52:24 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id NAA09038 for ; Mon, 25 Mar 1996 13:52:18 -0800 (PST) Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id IAA01095; Tue, 26 Mar 1996 08:39:53 +1030 From: Michael Smith Message-Id: <199603252209.IAA01095@genesis.atrad.adelaide.edu.au> Subject: Re: Intel P-Overdrive and Opti chipsets? To: rgrimes@GndRsh.aac.dev.com (Rodney W. Grimes) Date: Tue, 26 Mar 1996 08:39:52 +1030 (CST) Cc: msmith@atrad.adelaide.edu.au, hardware@FreeBSD.ORG In-Reply-To: <199603251723.JAA04977@GndRsh.aac.dev.com> from "Rodney W. Grimes" at Mar 25, 96 09:23:41 am MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hardware@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Rodney W. Grimes stands accused of saying: > > > > > Just wondering if anyone out there is using an Intel PODP5V > > (83MHz P Overdrive) in a 486 board based on the Opti 82C895. > > > > I've got one here that won't work unless the internal cache is > > disabled, however that yields performance around 1/5 that > > achieved with a 486DX2/66. > > > > Any ideas? (Anyone got one of these bastards working at _all_?) > > I have an idea, it is called WB cache coherency, and it probably > was not implemented correctly on your motherboard. Does your bios > only allow yot to disable the internal cache, or can you set it > to write through mode (like the 486 was). Several motherboards > have this as a jumper on the board. The board supports WB mode, and was previously running with it enabled. I'm fairly sure that the cache on the board works OK; it's been running FBSD for over 12mo. with a VLB busmaster SCSI controller. It wouldn't surprise me if the board is wrong, but I tried all of the possible combinations of internal and external cache and WB/WT modes, and the only significant factor was whether the PODP internal cache was on. > This is a common problem with the PODP processors :-( Think I'm resigned to hunting a new MB for this box. *sigh* Thanks for the suggestions. > Rod Grimes rgrimes@gndrsh.aac.dev.com -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[