I just saw the 7970 Lightning
but there was No HDMI on it! Why is it? Also with an adapter will I be able to get the same performance as a HDMI?
This is because, in the grand scheme of things, HDMI is no longer the "top" output. Everyday HDMI is limited to 1920x1200, while both DisplayPort and DVI-D can output 2560x1440. Also, while the 7970 Lightning has 6 outputs, you'll notice that only 2 are DVI-D. This is because Eyefinity requires all displays beyond the second to be driven by DisplayPort. If you have a third monitor that doesn't have DisplayPort you need an active
DisplayPort to HDMI/DVI-D adapter to output it with any Eyefinity enabled card.
Edit: looks like I haven't looked at that card in a while. Both DVI ports are single link, meaning they can output the same resolution as HDMI. DVI-D means that you have digital only (so you can't output to an analog [most commonly VGA] monitor through an adapter) while DVI-I has both digital and analog outputs (so you can use an adapter on that one).