uhm what ? You used that DP to DVI adapter and then a DVI-VGA adapter and connected the Old Monitor ?
VGA is a Analog signal! Using a passive DVi-VGA adapter only works with Analog signals! DP to DVI Adapter mostly create a digital Signal.
So i guess that was the Problem here.
But what makes me wonder... normaly AMD GPU's have i DVI-I and one DVI-D I = Analog+Digital D = Digital Only. But you have 2 passive DVI-VGA adapters connected (they're really really short, aren't they?) and both Monitors work.
@pickles
http://store.apple.com/ch-de/product/MB ... CH-Aff-PHGAnd to your question about 1920x1080 with two 1280x1024 beside... You can't create an Eyefinity desktop with that- But you can play Games in Windowed mode, or use SoftTH(DX9 games only) to span games!