There's another good possible reason why R9700pro not working with other boards..
There are two "revisions" on the R9700pro since their release.
I don't recall what number it was but the ones I had were all the first revision. Now, I'm not saying that is what's causing this, but it is a good, possible cause. A while back, we had a discussion on the revisions too. However, that is very bad if so. Whether it's first revision or not, it's not acceptable, plain and simple.
Don't tell me I'm a troll. You're just asking for it.
I'm pretty... damn ... pissed at ATI.