I have issues fully grasping the purpose of putting two or more graphics cards in one system.
SLI and Crossfire claim that they combine the power of multiple graphic cards. If I understand the information on the NVIDIA site correctly, SLI combines the processing power but the memory does not increase at all. I assume it's the same for Crossfire.
I see, in theory, where this makes sense if you use two GPU's to drive one graphics output port, although it does seem a bit of a waste considering that you kind of don't even use the memory on one of the cards. But what happens if you connect one monitor to one card each?
What I can't figure out at all, however, is the purpose of just two or more non-linked graphics cards in a system. Say I have just one monitor, is the second card used for anything at all? If yes, used by what, and how can I check or influence it? But even if I had two monitors, connected to each card, how would that work? I seem to understand that not each monitor would be driven by each card entirely separate. If this was the case, there would be no room for linked cards at all, right? So there must be some limitation, but what is it?
As you can see, I'm slightly confused about it all. If one could explain the difference between linked GPUs and non-linked GPUs, the benefits and downsides, in single and multi monitor setups, I'd appreciate it a lot.
By the way, in my setup I have two Nvidia NVS-300 cards but just one monitor. So I started wondering if the second card is doing anything at all and if yes, what that is.