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Date:      Thu, 30 Dec 1999 22:27:02 -0800
From:      Mike Smith <msmith@freebsd.org>
To:        tsikora@powerusersbbs.com
Cc:        "freebsd-stable@FreeBSD.ORG" <freebsd-stable@FreeBSD.ORG>
Subject:   Re: Temperature Findings 
Message-ID:  <199912310627.WAA00576@mass.cdrom.com>
In-Reply-To: Your message of "Thu, 30 Dec 1999 19:20:26 EST." <386BF6CA.EA00DF5C@home.com> 

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> I had one my technicians set up a scope to test the voltage readings and
> a Cooper temperature gauge to check the case temp. We decided to abandon
> the CPU test since we had no accurate way to attach the gauge. Our
> findings:
> The voltage readings by the winbond IC in the bios are accurate.
> The case temperature was 5F cooler than reported. 
> So I would conclude the readings from the bios are a fairly accurate
> representation of the machines current condition.
> 
> Things I failed to mention.
> The CPU's were overclocked by 100MHz
> Core CPU Voltage was raised a 1/2 step to 2.05V
> 
> o This still does not explain the differences between Linux
>   and FreeBSD. 

The difference has already been explained as a different instruction mix. 
This should be obvious to anyone that has been in the industry for as 
long as you have.

> o The standard 3.3-RELEASE UniProcessor kernel runs identical to    
> Linux.

This is because both systems use the HLT instruction, which has a low 
power consumption.  You've already been told this.

> o FreeBSD SMP kernels immediately run hotter than the standard      
> kernel.

FreeBSD doesn't use HLT in the SMP implementation.  You've been told this 
as well.

> I put Core voltage back to normal and set the CPU's to standard
> settings. The result was much better but it still runs about 14 degrees
> hotter.(acceptable) 26 degrees was not.
>
> Has anyone else checked this. Just checking the Generic versus a SMP
> kernel you should see this.

This is commonly known behaviour.  Your problem is simply that your 
cooling setup is not adequate to support your system running at 100% duty 
cycle.  You've been told this already.  You need to upgrade your cooling 
arrangements, and you've been told _that_ already too.

-- 
\\ Give a man a fish, and you feed him for a day. \\  Mike Smith
\\ Tell him he should learn how to fish himself,  \\  msmith@freebsd.org
\\ and he'll hate you for a lifetime.             \\  msmith@cdrom.com




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