New video cards practically are computers by themselves, meaning they have processing power in the card themselves. This is done to lift a processing weight on the main processor, but is done only on graphics. This mean that if you have one of those newer video card, the graphics are done only by the video card and sent to the processor to be then sent on the screen until the card can't take anymore and then the main processor do the rest.
Since DOS graphics are far from needing an enormous amount of power tough, the effects will probably be negligable unless you use some weird image improvement options.
What takes most power for DOSBox is the emulation and emulation always take an enormous toll on the CPU for raw power. High ram indeed help at lot here. If you don't have enough ram, the computer will need to switch to writting stuff on the HD slowing down the process a lot.
I think that's called "virtual memory" or something like that.
Edit: Lars, what's your problem with the VIP section?
