2 R9 280 GV-R927XOC-2GD

[lilfooker2469]

I bought 2 R9 280 GV-R927XOC-2GD  gigabyte cards. when i have them both on the mobo  and try to mine litecoin  the reboot the computer,  so opens cgminer  nothing but he cgminer 3.7.0 on the cmd window  about 1 min goes buy then reboot my computer

 i removed one and it mines fine , swapped and the other card mines fine also.
 i tried different driver, different cgminer  (currently using 3.7.0) even bfg miner.
also tried riser and swapping where the sit on the board
the psu is 1000
4 gig ram
gigabyte mobo
1 core cpu
im pretty much lost on how to fix it  any ideas would help


EDIT :
i got it to start mineing  low hash rate
by running
cgminer -o -u -p
 then turn the intestity up to 13 on the first card only hashed at 256 khs max
try turning the 2nd card uo to 13 and rebooted.