Hi brff15, we really do appreciate your efforts to help out...but unfortauntely your information is incorrect.
You can safely run 2 different speeds...and you can mismatch the motherboard and
ram - this will cause some compatability issues - yes...but it will not kill a motherboard.
And please do not resurrect an Answered thread...they have been marked as Answered meaning that no more input is required.
As I said earlier, we do appreciate your efforts to help out, just please make sure your information is correct before posting it.