amd64: Fatal Trap 12 in high load situations

Michael Powell nightrecon at
Sat Feb 6 10:38:46 UTC 2010

ms80 wrote:

> Hi
> I have a problem installing / upgrading FreeBSD 8.0-release on a new
> machine.
> The computers specs are:
> cpu: AMD Phenom II X4
> board: Gigabyte MA790GPT-UD3H
> ram: 4x2GBytes DDR3/1333
> hdd: 2xMaxtor STM31000528AS
> nic: 4x Intel(R) PRO/1000
> So here are my questions:
> 1. Are there any known caveats or quirks regarding my hardware?
> 2. What can I do to further investigate this issue
> 3. Not fully on topic but might be related: The buildsystem recognizes my
> cpu as "686 class cpu" wich is wrong. Are there any switches I can set in
> make.conf to have 'make' use the correct values? Currently I'm using a
> blank make.conf, meaning it is not present (as it is by default on a fresh
> installed system).

I am using this motherboard with an AMD x4 630 Propus cpu and 4G Ram 
(2x2GB). I have done a basic overclock to 3.36GHz with the ram running at 
1600MHz. This is my KDE4 desktop machine running FreeBSD 8 and all ports 
currently up to date.

When selecting the RAM to put on this motherboard you should have consulted 
the list from Gigabyte for approved memory and chosen very carefully. The 
memory I actually have was not an exact line item from the list, but it was 
something extremely close and which was designed and manufactured for use 
with an AM3 socket motherboard.

You will notice that some RAM today is designed for Intel P55 chipsets and 
Lynnfield processors while other RAM is designed specifically for AM3/AM2 
socket use. It is probably not a good idea to disregard this during 
selection, e.g. memory not specifically meant for AM3 socket mobos may not 
function correctly.

I also seem to recall seeing somewhere that this motherboard acquires 
limitations in overclocking when all 4 sockets are filled and the best 
overclocking results when only 2 sockets are in use. I am only using 2 
sockets in a 2x2GB arrangement for 4GB RAM total. If you are not 
overclocking and have all 4 sockets filled you may not be able to go above 
1066MHz memory multiplier. With only 2 sockets populated 1333MHz should be 

I believe your problem centers around memory. It may not be designed for AM3 
socket and/or may not be able to handle a higher memory multiplier. When I 
first put this motherboard in I attempted to boot from an already installed 
OS with the memory multiplier set too high and saw numerous examples similar 
to what you are describing. Since I had bought 1600MHz memory I mistakenly 
set the multiplier too high. When I set it back to 1333MHz everything was 
fine. Either the memory multiplier is set too high for your RAM or it is 
just the wrong RAM to begin with.

As far as make.conf goes I use: CPUTYPE?= k8


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