Hi all. I purchased a rampage 3 extreme to use with my 6990s but the northbridge is overheating. Some people with similar trouble are recommending replacijg the tim but since that is permanent im thinking about just conisdering another board. Question is. If its overheating with just one card. Even if i replace the tim with arctic silver will the passive sink be enough for all four cards? or am i just destroying a mb warranty for no good reason?