Date: Wed, 27 Nov 1996 11:00:52 -0800 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: Steve Passe <smp@csn.net> Cc: Bruce Albrecht <Bruce.Albrecht@seag.fingerhut.com>, smp@freebsd.org Subject: Re: P5 vs. P6 performance Message-ID: <199611271900.LAA05971@MindBender.serv.net> In-Reply-To: Your message of Wed, 27 Nov 96 10:18:00 -0700. <199611271718.KAA15456@clem.systemsix.com>
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>> I'm looking at buying either a dual CPU Pentium motherboard and
>> initially populating it with a single Pentium-200 MHz, and then adding the
>> second Pentium-200 MHz a few months later, OR buying a single Pentium-Pro 200
>> MHz motherboard. What can I expect for relative performance for each
>> system, assuming that each one has, for example 64 MB memory? If this
>> is an overpowered home system with only occasional periods of
>> sustained computation, would I need more that 64 MB?
I have 64MB now. With memory so cheap, it makes a *perfect* system.
I never ever push anything out to swap. :-) It's really overkill for
my home system -- 32MB was working nicely. But, once again, if memory
is so cheap, why not...
>> For example, on a lightly loaded system, how much faster is the
>> Pentium Pro? Which system (dual P5 vs. 1 P6) would be faster at
>> compiling all of FreeBSD from scratch?
My experience shows that a P6-200 (256K cache) is roughly 2.5 times
faster than a P5-120. Remember also that a P5-200 is *not* 200/120
faster than a P5-120. The P5-200 is reaching bus saturation levels,
and supposedly is barely faster than a P5-166. I would suspect that
putting two of them in there would only make matters worse, unless you
had some really exceptionally designed, and BIG, motherboard caches.
This is NetBSD-1.2, but the times are similar to FreeBSD. I can do a
make world, from a virgin tree to finished, in 1 hour 21 minutes on a
P6-200 w/64MB, an Adaptec 2940UW, and some decent SCSI drives. It
takes ~3:15 on my P5-200 (single processor) 2/64MB, 512K PB cache,
same SCSI controller and drives.
>right now the single P6 would be faster than 2 P5s. How much longer that will
>be true I'm not sure, things are progressing nicely in the SMP kernel.
I would suspect that dual P5s would only be slightly faster than a
decent P6 system. That is pure speculation, though.
>2 P5-200 might suffer from serious bus congestion. If you can afford it
>go for a dual P6 with one CPU for now, then add the second CPU when
>finances permit.
This would definitely be the best advice for performance reasons.
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
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