Overheating 8800 GTX OC2's ?

Hi there guys i recently fitted 2 new graphics cards:

BFG 8800 GTX OC2's

my issue is i think .. overheating, as my games lock up at various times and the issues were not present with my 7900 gtx's the only different this time is

I have a new soundcard right above the top (no other place to put it) 8800 its the asus xonar, when it overheats the sound card shroud (aluminium) gets just as hot as the 8800's so my thoughts are to move into water cooling, unless you guys have any other ideas

and if water cooling, I'm interested in good makes and manufacturers as although I've worked on my pc performance overclocking and such over the years water cooling is a beast i have never tackled, so any big points to avoid or definatly do would be great

i was looking at koolance water cooling but please suggest anything

Have you tried running with onboard sound to eliminate the possibility of soundcard driver issues aswell as taking the heat buildup out of the equation??