1. The higher the resolution, the lower the performance. See following review as an example:http://www.xbitlabs.com/articles/video/display/nvidia-geforce-gtx-460.html
2. All PC monitors have DVI and/or VGA ports. Only very cheap monitors do not have DVI ports.
I've swear I've seen some pc monitors with only HDMI ports......
And those are far from "cheap"