...
I did back off on my GPU Settings (HD5870 -> 850/1200/1.175, I6) and i got the same results... my rig is locked up.

. Can I consult any file where is wrote what happened before my rig is locked up?
If you run cgminer also with "-m logput.sh" and put logput.sh in the current directory when you start cgminer
and on another machine with IP address IP run
./logget.shlogput.sh (change IP to the target IP address)
#!/bin/bash
#
cat | nc IP 7777 &
ncpid="$!"
trap "kill $ncpid" SIGINT SIGTERM EXIT
wait
logget.sh
#!/bin/bash
#
while true ; do
echo "`date`: Opening new reader"
nc -l 7777
echo "`date`: Reader exited"
done
Then the target machine will see the log.
Or even in the target machine to see and save the log:
./logget.sh 2>&1 | tee log.log