what role does a graphic card play?

[Video-Pal]

What role does a graphic card play in video capture/editing/authoring etc? In other words what advantage do the expensive graphic cards have over say the rock bottom integrated graphics?

[sterno]

In general, the video card plays a very minor role. However, you want to avoid the rock-bottom integrated chipsets because a lot of them use a crappy shared memory architecture where part of your system RAM is used for video memory, but it all runs over the same bus. That slows your entire system, I've known people who saw noticable improvements just in ordinary day-to-day use like Office apps and web surfing after installing a $20US 4MB PCI card.

[txpharoah]

In general, the video card plays a very minor role. However, you want to avoid the rock-bottom integrated chipsets because a lot of them use a crappy shared memory architecture where part of your system RAM is used for video memory, but it all runs over the same bus. That slows your entire system, I've known people who saw noticable improvements just in ordinary day-to-day use like Office apps and web surfing after installing a $20US 4MB PCI card.

I'll go along with this explanation too. I'd have said it different, but this does the job.