To be honest, I've had problems with Asus in the past before too. Fortunately not lately though. But you're right: they are not completely without fault also. That is one reason I started using Intel motherboards at one time. Those boards were very good, but afaik Intel doesn't make 'em anymore nowadays I believe. This is also the main reason I'm now looking towards Supermicro. They are known for their stable server motherboards, and now they have created some consumer motherboards as well. I have good hopes for them.

Good to read you've finally been able to pinpoint the root of the problem! Glad to be of help, even if it only was pointing you in the right direction.