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Date:      Thu, 23 Sep 2010 23:56:31 -0700
From:      John Theus <john@theusgroup.com>
To:        FreeBSD Stable <freebsd-stable@freebsd.org>
Subject:   Re: SuperMicro i7 (UP) - very slow performance 
Message-ID:  <20100924065636.BAF5E5F4C@theusgroup.com>
In-Reply-To: <4C9B0F2C.20601@FreeBSD.org> 
References:  <mailpost.1285173904.332223.70365.mailing.freebsd.stable@FreeBSD.cs.nctu.edu.tw> <mailpost.1285202775.8039756.86645.mailing.freebsd.stable@FreeBSD.cs.nctu.edu.tw> <4C9B0F2C.20601@FreeBSD.org>

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Alexander Motin wrote:
>Just to compare, my Core i7-870 with boxed cooler reports:
> 31C being idle with tuned power management,
> 53C being idle without any power management,
> 85C during `make -j16`.
>That system did `make -j16 universe` in about 3 hours AFAIR.

Another data point and a comment about temperatures.
  i5-650/H55, half the cores and about 60% the cost compared to the above.
  8.1-STABLE amd64
  make -j16 universe in 4 hours 5 minutes.
  all cores running at 100% according to top -P
  30C idle
  42C max during make

I'm a EE and I used to make my living designing microprocessor-based computers.
Our design standard for maximum chip temperature was 45C. Above that and the
MTBF starts falling fast. Today's motherboards have a lot fewer components, so
45C is too low if you have a single motherboard, but not if you have 100.

For the i7-870 above, the intel datasheet says at a maximum power of 95w, the
maximum permitted temperature is 72.7C. For the i5-650 at 73w, the maximum
permitted temperature is 66C.

John Theus
TheUsGroup.com



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