Max resolution for graphics card

You need the dual-link dvi cable to get 2560x1600. Theoretically, some of the newer revisions of the HDMI standard allow 2560x1600 and higher, as long as you're only using 24 bits per pixel, but there are very few video cards or monitors that actually support more than 1920x1200 over hdmi, and I think you might need to make sure the hdmi cable supported the newer revision as well. The best way to understand the difference between dvi and hdmi is to look them up in Wikipedia.