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Date:      Fri, 21 Mar 2003 11:47:48 -0500
From:      "Ryan Watson" <watsonr@gulliver.summitoh.net>
To:        <ekgermann@cctec.com>
Cc:        <freebsd-isp@freebsd.org>
Subject:   Re: Maximum recommended user limits on mail server
Message-ID:  <00fe01c2efc9$aae69ba0$d70d10ac@summitoh.net>
References:  <NDBBJJPLIGJGLBKILFIHOEGLJMAA.ekgermann@cctec.com>

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I have come to learn that this is all because the memory address portion of
the Xeon is 36bits, not 32.  Though the Xeon is indeed a 32bit CPU.

Ryan

> It isn't physics.  A Xeon with Intel ® E7501 Chipset Memory
> Controller Hub (MCH)
>
> ftp://download.intel.com/design/chipsets/datashts/25192701.pdf
>
> Page 120
>
> 5.5 System Memory Controller
> The MCH can support DDR 266 and DDR 200 using SSTL_2 signaling. The MCH
> includes
> support for:
> . In dual-channel mode, up to 16 GB of 266 MHz or 200 MHz DDR SDRAM
> installed for a
> maximum address decode of 16 GB - 64 MB unless memory reclaim feature is
> used.
> . In single-channel mode, up to 8 GB of 266 MHz or 200 MHz DDR SDRAM
> installed for a
> maximum address decode of 8 GB - 32 MB unless memory reclaim feature is
> used.
> . DDR 266 or DDR 200 registered 184-pin ECC DDR SDRAM DIMMs
> . 72-bit wide x4 and x8 DIMMs using 128-Mb, 256-Mb, and 512-Mb SDRAM
> technology.
> . Maximum of four DIMMs per channel, single-rank and/or double-rank
> . Cache Latency of 2 and 2.5 only.
> The eight chip select lines support up to eight rows of double-rank SDRAM
> DIMMs. The MCH
> does not support non-ECC DIMMs or unbuffered DIMMs.
>
> This is the support chip for the Xeon processor.  So yes Virginia, it does
> support more than 4GB per processor.  Point your Sparky at
> http://www.intel.com
>
>
>
> > -----Original Message-----
> > From: owner-freebsd-isp@FreeBSD.ORG
> > [mailto:owner-freebsd-isp@FreeBSD.ORG]On Behalf Of Ryan Watson
> > Sent: Thursday, March 20, 2003 7:32 AM
> > To: Tom Samplonius
> > Cc: freebsd-isp@FreeBSD.ORG
> > Subject: Re: Maximum recommended user limits on mail server
> >
> >
> >
> > >   You should probably look that up.  Even the lowly Dell Poweredge
2650
> > > has a 8GB memory limit.
> >
> > That's because it's more than one CPU, each x86 can address only 4Gigs.
> > Trust me on this one, it's physics.  BTW, are you a Dell salesperson?
Sit
> > down with a piece of paper, and figure out what the largest number you
can
> > come up with, with only 32 bits?  Oh yeah, that means you do it
> > with a base
> > of 2, not 10.
> >
>
>
>


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