From owner-freebsd-smp Mon Jun 21 10: 6:27 1999 Delivered-To: freebsd-smp@freebsd.org Received: from par28.ma.ikos.com (par28.ma.ikos.com [137.103.105.228]) by hub.freebsd.org (Postfix) with ESMTP id D25C715034 for ; Mon, 21 Jun 1999 10:06:24 -0700 (PDT) (envelope-from tich@par28.ma.ikos.com) Received: from [[UNIX: localhost]] ([[UNIX: localhost]]) by par28.ma.ikos.com (8.8.7/8.8.7) id NAA18274; Mon, 21 Jun 1999 13:06:10 -0400 From: Richard Cownie To: Kedar Rajadnya Subject: Re: SMP, 4GB RAM, 4x CPU Date: Mon, 21 Jun 1999 12:37:47 -0400 X-Mailer: KMail [version 1.1.0] Content-Type: text/plain Cc: freebsd-smp@FreeBSD.ORG References: <2.2.32.19990621154926.01faf7e8@asacomputers.com> MIME-Version: 1.0 Message-Id: <99062113061000.18239@par28.ma.ikos.com> Content-Transfer-Encoding: 8bit X-KMail-Mark: Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Mon, 21 Jun 1999, Kedar Rajadnya wrote: > >2) To get the use of 4GB dram, I am running 19990604-CURRENT. This > > has problems with 4GB dram (but I've submitted a fix), and also > > This is just a question. Do you think it would be better to use > something like an Alpha 264DP in dual-cpu format(upto 4MB cache) and 4GB RAM > rather than a quad xeon, 4GB RAM and a 32-bit bus? > > Kedar. I've never used an Alpha myself. From the benchmarks I've seen I believe they are substantially faster for floating point, and they have more memory bandwidth and bigger caches. So if absolute performance on floating-point intensive stuff is what you need, Alpha is worth considering. However, if price-performance is what you need, I believe a dual-Celeron at 500MHz+ with 1GB dram for $3K is about the best you can do. As far as I know the dual-Alpha systems are still up in the $10K range. This may change next year. A couple of months from now K7 systems may also be interesting (though I think we'll have to wait a while for cheap SMP-K7 systems). Also there are rumours that Alpha performance is critically dependent on the compiler used - i.e. the DEC compiler on Tru64 Unix (is that this week's name ?) might give you 30% more performance than gcc. This is third-hand information, so may be false (or it may be true for Alpha 21164 but not 21264, which I think does more dynamic scheduling ?). Be wary of the SPECint/fp results - these may be heavily influenced by the cache size, and maybe also wacky compiler options which are rarely usable in real life. As always, the correct choice depends on your particular application and financial constraints. Richard Cownie (tich@ma.ikos.com) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message