Originally posted by: Sylvanas
Because they want you to buy their more expensive Crossfire/SLI capable cards along with their own Nvidia/AMD multi-GPU capable motherboard chipsets.
I think the OP is saying. in essence, that he wants
all motherboards/video cards to be like that.
To the OP:
Particular circuitry is required at the motherboard/chipset level in order to provide for two video cards operating a single monitor, without this circuitry it won't be possible.
Another option, instead of SLI/CF, would be multi GPU video cards. like 3DFX's
3DFX Voodoo 5000 (dual GPU) and
6000 (quad GPU) cards. But then if these cards were SLI/CF capable, two of them could be used for increased performance.
SLI/CF provides ultimate performance, and a convenient upgrade path to that ultimate performance. So, if you want to go there, SLI/CF is a good way to get there.