Toke,
I actually have two 1900s running three 30inch screens in asia. I tried to correct that in the post but failed edit. 😕
I was going to try the fourth 30 inch screen, but like I said the heat is so incredible, and I am up against thermal limits already with the fans reving way up. I'm afraid I have cooked my 1900 card that's pulling two of the flatscreens. I talked to applecare who patched me through to a tech who agreed I'm way too hot. Of course he wants me to bring the whole thing in, but my machine is across the ocean and I'm disabled anyway so that's out.
But the 1900 are vertiable hair driers and are cooking the whole macpro imho. I'm going to move the whole affair in front of an airconditioner and pipe a hose with a fan to the front of the macpro.
Expensive and noisy, but I can't get parts in the country I'm in. This has become an expensive experiment!