From Fedora Project Wiki
Two DELL displays 20" and 19". Mirroring/cloning in native resolution passed, display extension is limited to 1600x1600, I'd need 1600+1280 px in width at least.
Screen 0: minimum 320 x 200, current 1600 x 600, maximum 1600 x 1600 DVI-I-0 connected 800x600+0+0 (normal left inverted right x axis y axis) 367mm x 275mm 1600x1200 60.0 + 1400x1050 74.8 60.0 1280x1024 75.0 60.0 1280x960 60.0 1152x864 75.0 1024x768 75.0 70.1 60.0 832x624 74.6 800x600 72.2 75.0 60.3* 56.2 640x480 75.0 72.8 75.0 59.9 720x400 70.1 DVI-I-1 connected 800x600+800+0 (normal left inverted right x axis y axis) 376mm x 301mm 1280x1024 60.0 + 75.0 60.0 1280x960 60.0 1152x864 75.0 1024x768 75.0 70.1 60.0 832x624 74.6 800x600 72.2 75.0* 60.3 56.2 640x480 75.0 72.8 75.0 59.9 720x400 70.1