GeForce GT640 - 3 monitor setup question

[cpuken]

I've been running a 3 monitor setup on my recently purchased Zotac GeForce GT640 for several days now. The 3rd monitor in the setup is actually a Samsung Syncmaster monitor/TV. I normally will be watching a TV program on that monitor via a cable TV hookup but occasionally I'll switch the source and it will become the 3rd monitor in my setup.
I'm new to this aspect of computing so forgive me if these are really dumb questions... I just don't know how this segment of the PC operates:

1. My question is does it put extra load on the Video card when you run 3 monitors? Is there less load with 2 or 1 monitor?

2. Does it matter if the 3rd monitor is off or switched to an alternative source?

I'm guessing the video card is outputting signals on all three of it's ports (in my case the 2 DVI and 1 HDMI ports) and it does matter if there's anything connected there are not. In my theory, 1, 2 or 3 monitors connected and active doesn't matter the video card is working the same amount.

Thanks in advance for clearing this up for me.
Ken

 

[spmike]

The main issue is it takes more video memory if you are extending your desktop on the 3rd monitor as a separate screen (as opposed to cloning). It also take a little more GPU power for the same config, so you might notice a little performance drop when gaming, but not otherwise. You could always disable the 3rd display when gaming if it's an issue.

It won't hurt anything if the 3rd monitor is off or switched to another source.