Very nice man, and thanks for your time. You've answered a lot of questions.
What I'd like to know is do you really need a fan over northbridge, and how is the heatsink on R3 compared to R2? Bigger, smaller? Can't compare it from pictures and the plastic shround on the R3.
As I can see, you're running it at 4.6GHz@1.47V. That's something I was using earlier, though my frequency was 4.7GHz. Next step if time allows you would be to stress test the system and post temperatures from the new AI Suite 3 if possible, I'd really love to do that. And try it without the fan on the NB
It would be great if we could see how much the system really gets without any ghetto mods.
Considering 40mm fans, I have quite some experience with them. Best one I have is a xilence one, you need to make sure not to get a cheap no-name one since they basicly just spin around and do nothing. The xilence one does move some air, like 7CFM or so but it's something at least. Other options are like I wanted to do, the Delta ones, but as you've guys said it's impossible to put it there.
If this one could fit anyhow it'd be great... but it's 2CM thick