Motherboard temp is what I was going for. Everyone just calls it case temp.
Yeah thats hot too, but apparently unavoidable unless you turn some A/C on. So really you have no choice but to turn down your overclock. What kind of temps does 3.6ghz give you? Honestly I wouldn't go over 80c. I would say get a better cooler but you pretty much have the best air cooler there is.
The best thing you can do now is to get better case ventilation. How many fans do you have? And what size are they? Your case temps are 20 degrees F more than ambient, so if you can drop the temps inside that would help. And also, if you have good enough ventilation leaving the side of your case on actually gives you lower MB temps. As a bandaid right now, if you went and got a large house fan or whatever and left the side of the case open and blew direct air in there to cool it that would work pretty well.