I had been running into the same issue with a H110i GT cooler. I found the mod that airdeano suggested many of time when researching the problem. I ended up using the rubber mount bushings that came for mounting fans on my 760t case. Although it hasn't been the most ideal temps and solution it did help. Like you, i was hitting 90 to even 100 with the simplest of tasks and you could wiggle the block noticeably even though the screws were all the way tight. Now that i have the rubber spacers in there I hit maybe 60c on a 10 min stress test with a decent overclock. Give the spacers a try if you havent, O rings can be bought for like 25 cents at a auto parts store.