Cannot add new mode in xrandr for external monitor

Today I was trying to connect my second monitor to my notebook. I have: - nvidia graphic card - 304.43 drivers [support xrandr 1.2] - archlinux [up-to-date] - awesome wm - xrandr 1.3 My problem is with bigger resolution than 640x480 for my external monitor (VGA). xrandr -q: Screen 0: minimum 8 x 8, current 1920 x 800, maximum 8192 x 8192 VGA-0 connected 640x480+1280+0 (normal left inverted right x axis y axis) 0mm 640x480 59.9*+ 320x240 120.1 LVDS-0 connected 1280x800+0+0 (normal left inverted right x axis y axis) 331m 1280x800 59.9*+ HDMI-0 disconnected (normal left inverted right x axis y axis) As we can see the is no higher resolution fo VGA, so I add new mode: xrandr --newmode $(gtf 1280 1024 70.4 | grep Modeline | sed s/Modeline\ // | tr -d '"') I checked avaible resolution and refresh rate under windows: one of them was 1024x768x70 (OSD of my monitor said that it is 70.4HZ). After create new mode, I wanted to add it: xrandr --addmode VGA-0 1280x1024_70.40 And... It failed: X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 153 (RANDR) Minor opcode of failed request: 18 (RRAddOutputMode) Serial number of failed request: 29 Current serial number in output stream: 30 From google I learned that in older xrandr / nvidia drivers was problem with list of avaible modes, but now with support of xrandr 1.2 by nvidia drivers it should be better. I also try with lower resolution and refresh rate (eg. 1024x768x50), but I've got the same error. I'm out of ideas what to do with this problem...