Im trying to make customs resolutions based on the xrandr, but when trying the relutions via the display utility, it gets a black screen only. I dont know if this could be a issue of the driver or the video card (since its taking 2 or GB for vram automatically and whithout the chance of selecting the amount of ram used)
VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev c2)
with the module
Not using ubuntu, but fedora and suse.