There is a lot to be said for twin Cards that are not SLI’d. First I have 2 systems set up this way. Vegas 10 on one, AE on the other. Both systems have Windows 7 64 bit. Each have 2 monitors (2-1920×1080 & 2-1680×1050). In win7 each core can offload ‘routine’ math to the GPU, and it doesn’t matter which GPU when it has access multiple ones. So even before we fire-up our favorite video program we already have an increase in overall system speed.
Second, having both monitors plugged into the same card will definitely impact graphics performance on any machine.
John is absolutely correct in saying that “buying a better video card” is a better choice, if you have a single monitor.
Since I need all the screen real estate I can get, I will never build a system with less than 2 video cards driving 2 monitors.
Jeff
http://www.narrowroadmedia.com