How do I output display at 2560x1080? (am trying to add modeline with xrandr)

Solution 1:

I have connected ultrawide monitor by HDMI with

Modeline "2560x1080_40.00"  147.25  2560 2680 2944 3328  1080 1083 1093 1108 -hsync +vsync

I used:

cvt 2560 1080 40

HDMI did not support > 165 Mhz, however HDMI 1.3 supports up to 340 MHz maximum pixel clock rate wiki.