hot temps causing system lock ups....

[Copenhagen69]

ok i just got a silverstone TJ-09 and installed all my stuff...

i got 2 8800GTX in SLI

but when i play any for for awhile my system just freezes....im guessing this is because of hot temps....

i have a temp monitor on and its takin temps between the the 8800's and it was getting to 60-65C between there...
the actual cards are at....
#1 (top) around 65-70C
#2 (bottom) around 55-60C

my CPU was at 50-50C it is a AM2 x2 4600 my CPU cooler is a zalman cnps9500

i have fans in every slot i can for this case.... ( 2 120's at top....1 120 in back....1 120 middle and 1 120 on HDs....


so i guess my question is....is it my video cards gettin to hot and locking the system....
or is it my CPU getting too hot and locking the system....
my wiring is pretty good....there are hardly any wires over the mobo nor are they blocking the mid fans air flow to the video cards....

any ideas how to lower the temps to keep my system from locking up?