VC Spanned across 2 dell 2405

hi all,i did an experiment yesterday and i spanned my VC across my 17"CRT just to see it it works, i also have a Dell 2405 as my main monitor,i was quite pleased with the results and never saw any frame rate problems, anyone know why this was the case?anyways it was very pleasing to see so much more! so now i am wanting to get another dell 24 to increase the immersion factor, i want to know if my GPU will have any problems with another monitor, as i didnt have any problems hooking up my 17"CRTalso any idea why when i am in spanned view why the plane sits in the middle of the monitor in external view?thanks.