| What is your graphics card model? NVIDIA Corporation GK208 [GeForce GT 720] This does 4K | Which driver are you using? I am using the NOUVEAU at this time | What connector are you using (DVI, Display Port, HDMI)? HDMI | Does it work at 4k with Gnome, or KDE? Yes has worked under Gnome The /var/log/X log file shows it present from the monitor. grep 3840 /var/log/Xorg.0.log [ 6.540] (II) NOUVEAU(0): h_active: 3840 h_sync: 3888 h_sync_end 3920 h_blank_end 4000 h_border: 0 [ 6.540] (II) NOUVEAU(0): h_active: 3840 h_sync: 4016 h_sync_end 4104 h_blank_end 4400 h_border: 0 [ 6.996] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 6.996] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 7.104] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 7.104] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 8.290] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 8.290] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 11.932] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 11.932] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 13.939] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 13.939] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 14.076] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 14.076] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 14.212] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 14.212] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 14.349] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 14.349] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) [ 14.624] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 533.25 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync (133.3 kHz eP) [ 14.624] (II) NOUVEAU(0): Modeline "3840x2160"x0.0 297.00 3840 4016 4104 4400 2160 2168 2178 2250 +hsync -vsync (67.5 kHz e) I find no errors throwing out the mode. Thanks, Jerry