i notice that the card has 4 ports out of which 1 is hdmi. As far as i know, only hdmi supports 1080p.
is this true or can the other ports output 1080p?
All of the ports: DVI, HDMI and DP support 1080p. DVI being used the most in computers - it's the most reliable one and doesn't carry unneeded information like HDMI (sound).
1080P is just the 1920x1080 resolution. As mentioned above each of those outputs support that resolution. The P means progressive scan, but lets not go into that.