Ok ive replaced it with a 500w PSU now...
Now i Just need too wait a while and copy a crap load!!!
Problem normally accurs once copy rate reaches 50MB/s.
For those interested i did a mbmon with new PSU:
[root@gw2 /home/thavinci]# mbmon
ioctl(smb0
pen): No such file or directory
Temp.= 255.0, 240.0, 243.0; Rot.= 11250, 135000, 67500
Vcore = 2.29, 3.17; Volt. = 3.31, 5.05, 2.25, -0.00, -3.08
Temp.= 255.0, 240.0, 242.0; Rot.= 11250, 135000, 67500
Vcore = 2.24, 3.17; Volt. = 3.31, 5.05, 2.25, -0.00, -3.08
Temp.= 255.0, 240.0, 243.0; Rot.= 11250, 135000, 67500
Vcore = 2.26, 3.15; Volt. = 3.30, 5.05, 2.25, -0.00, -3.08
Temp.= 255.0, 240.0, 243.0; Rot.= 11250, 135000, 67500
Vcore = 2.40, 3.15; Volt. = 3.33, 5.05, 2.25, -0.00, -3.08
Temp.= 255.0, 240.0, 244.0; Rot.= 11250, 135000, 67500
Vcore = 2.40, 3.17; Volt. = 3.31, 5.05, 2.25, -0.00, -3.08
^C