gpu mining with sapphire 7950 dual x shutdown problem

[kashifrazzaq20]

i am facing shutdown problem sapphire 7950 dual x
i am using this script in cgminer

cgminer --scrypt -o stratum+tcp://pool.com:3322 -u user.worker -p x --intensity 13
it work fine but giving me just 250 kh/s to get high kh/s i have to change intensity 13 above but when i try 14,15,16,17,18,19 my computer direct shutdown and screen blank..

please help me..

PSU 800W

cpu is good

OS Name   Microsoft Windows 7 Ultimate
Version   6.1.7601 Service Pack 1 Build 7601
Other OS Description    Not Available
OS Manufacturer   Microsoft Corporation
System Manufacturer   Hewlett-Packard
this is my system
System Model   HP xw9400 Workstation
System Type   X86-based PC
Processor   Dual-Core AMD Opteron(tm) Processor 2218, 2600 Mhz, 2 Core(s), 2 Logical Processor(s)
Processor   Dual-Core AMD Opteron(tm) Processor 2218, 2600 Mhz, 2 Core(s), 2 Logical Processor(s)
BIOS Version/Date   Hewlett-Packard 786D6 v02.07, 12/8/2006
SMBIOS Version   2.5
Windows Directory   C:\Windows
System Directory   C:\Windows\system32
Boot Device   \Device\HarddiskVolume2
Locale   United States
Hardware Abstraction Layer   Version = "6.1.7601.17514"
Installed Physical Memory (RAM)   4.00 GB
Total Physical Memory   3.50 GB
Available Physical Memory   2.23 GB
Total Virtual Memory   7.00 GB
Available Virtual Memory   4.00 GB
Page File Space   3.50 GB

[kozmos]

Try it with another PSU, to make sure is it about your current PSU or not.

Good luck and I hope this problem will be solved.



Edit: can you also post the +12 readings of your PSU?