hmm some question

i have a 930i7 at 4.0ghz for daily usage but i am having a quite amount of heat in here cuz my ambient is not that good..around 35+ so my settings for 4.0ghz seems to stable at linx 768mb mem but only 10 loops...but it fails on 1536mb mem on 10 loop....also the temp of the 768mb full load is around 89c and 91c for 1536mb...i am goin to fix this damn temp by getting better fans for my casing but my question is, does stable in 768mb 10 loops can give stability on daily usage? i mean is it enuf? or is it the temp that giving me problem to get stable in 1536mb linx?