amd64: Fatal Trap 12 in high load situations

Michael Powell nightrecon at
Sat Feb 6 13:37:47 UTC 2010

ms80 wrote:

> Thank you for your reply.
> I'm using two of this: OCZ3P1333LVAM4GK
> (OCZ DDR3 AMD Edition, rated for 1333MHz at 1.65V). My Board is rated for
> 1066 - 1600 MHz memory, and neither the website nor the manual say
> anything about limitations with memory. Anyway: I didn't overclock cpu or
> memory. I have stability and long life in mind, so I try to keep the
> hardware cool. During testing I underclocked the memory with 1066 and 800
> MHz which didn't help: The machine crashes anyway. The only thing to note
> is that by default the board tries to set 1.5V DDR3 Voltage which is
> wrong, you have to set it to 1.65V manually.
> A faulty piece of hardware was the first thing I suspected and I tested
> among other things the memory with memtest86+. This runs fine for 4
> passes, without any error. As far as I can tell, my memory subsystem is
> ok.

Poking around in the OCZ forum for something I thought I recalled seeing 
somewhere before. I had seen reports that this board might be touchy about 
1.65v memory. As far as the consensus goes with the small sampling I looked 
at, it seemed that 1.63 or 1.64 vdc was the sweet spot. Some claims are that 
it didn't want to work at anything either above or below this range.

My RAM is OCZ3BE1600C8LV4GK (anything with BE or AM in the part number is 
designed specifically for AM3). I thought it was 1.5v, but since I didn't 
remember for certain I checked and it shows a spec for 1.65v. However, I 
rebooted so I could look at the CMOS/BIOS stuff and I have the System 
Voltage Control section set for "AUTO" for all. Then I looked in the "PC 
Health Status" page and on the "DDR3 1.5V" line it was only reading 1.600v.

There seems to be a general feeling the newer AMD processors don't much care 
for higher memory voltages. Try lowering your voltages and see if it helps.

I am successfully using this board with the CPU clock set at 240MHz, which 
with the x14 multiplier results in 3.36GHz operation. The Hypertransport and 
FSB bus speeds are 2400MHz and the memory is running at 1599MHz at the x6.66 
multiplier. When I get the RAM up to 1680MHz is where I can get it to 
freeze. As long as I don't do that it is totally stable.


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