i have just turned on the system this morning and the hissing has stopped untill about 5 - 10 mins in when it slowly started to come back. i guessing as the components got hotter. this is what makes me think it may be the gpu fan. i havent stopped the gpu fan when testing i just lowered the speed. so if i remove the card it may stop. well i hope.
Just took the GPU out and ran the comp for about 5 - 10 mins and no hissing, as soon as i put the card back in it started to hiss again. i hope it would be the graphics card and not the brand new mobo
This isnt a problem as im looking to soon upgrade to the GTX460
also I stopped the fan with my finger and the hissing was still apparent so I assume that it is one more of those caps. Thanks for all the posts guys