Date: Wed, 7 Apr 1999 02:54:33 +0100 From: Mark Ovens <marko@uk.radan.com> To: Darren Pilgrim <dpilgrim@uswest.net> Cc: "Dragon Knight ][" <dragonknight@dtgnet.com>, FreeBSD Questions <questions@freebsd.org> Subject: Re: K6-2/333, was: Re: Debug kernel by default (was: System sizewith -g) Message-ID: <19990407025433.C4453@marder-1.localhost> In-Reply-To: <3709EDEB.BE17A2E8@uswest.net>; from Darren Pilgrim on Tue, Apr 06, 1999 at 04:20:11AM -0700 References: <Pine.LNX.4.04.9904051605450.10244-100000@hades.riverstyx.net> <3709569A.70EEC38A@uswest.net> <37097B00.2186EB92@dtgnet.com> <3709EDEB.BE17A2E8@uswest.net>
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On Tue, Apr 06, 1999 at 04:20:11AM -0700, Darren Pilgrim wrote: > "Dragon Knight ][" wrote: > > Darren Pilgrim wrote: > <snip> > > > While this is mathematically and theoretically sound thinking, tests > > > have shown that there is little CPU/memory performance gain with a > > > 100MHz bus. Just take a look at www.tomshardware.com. As for my own > > > systems, I run K6-2 333s at 5x66 just because it sets the PCI and AGP > > > clocks at their spec'd rate of 33 and 66MHz, respectively, while > > > providing the CPU's spec'd 333MHz. > > > > > > > As you say, there is a little CPU/Memory performance increase at 100MHz fsb. > > So I do not see your logic in setting your chips at 5x66 because it puts your > > PCI and AGP where they should be. One of the 'specs' of the 100MHz fsb is > > that PCI and AGP cards will run at their normal speed of 33 and 66MH. I believe > > this is also true of the 95MHz busses. > > Actually I said "there is little", I didn't put an "a" in there. Plus > the only performance increases I've ever seen are on stress-test > benchmarks where the disk, memory, and video are all in use at once. > This situation is purely for performance testing, there's is no real- > world application. > > 95MHz produces slower AGP/PCI clocks and, lacking a performance gain > with a faster FSB, using 66MHz to get faster AGP/PCI clocks makes more > sense if your CPU isn't rated for a 100MHz multiple. This is just > splitting hairs; IRL, a <4MHz clock difference is nothing performance > wise. Your cards might complain about it though. Particularly the > ones that rely on the bus-clock for their internal clocks, like some > sound and video cards. > As the person who effectively started all this discussion about bus speeds and multipliers I just want to thank all the contributors to this thread. I now have a better understanding of how it all works. The fundamental misunderstanding I had was that the CPU itself did the mutliplication and that the m/b jumpers simply "told" the CPU what multiple of the bus speed to use. I guess that AMD only state 95MHz & 3.5X, and not 66MHz & 5X, because it gives the maximum absolute performance of the chip as the CPU <==> memory is running at its highest speed. > -- > dpilgrim@uswest.net /\ / __ Our lies are merely the > gryph@mindless.com / \/OC/URNE truth of another world > ICQ: 29880099 Death is not a kill -9, just a > DALnet: anim0s make world and shutdown -r now PGPKey available > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > -- FreeBSD - The Power To Serve http://www.freebsd.org My Webpage http://www.users.globalnet.co.uk/~markov _______________________________________________________________ Mark Ovens, CNC Apps Engineer, Radan Computational Ltd. Bath UK CAD/CAM solutions for Sheetmetal Working Industry mailto:marko@uk.radan.com http://www.radan.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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