sounds like the nouveau kernel module fails to drive them properly, please provide dmesg when booting without nomodeset & nvidia installed
** Package changed: xorg (Ubuntu) => xserver-xorg-video-nouveau (Ubuntu) ** Changed in: xserver-xorg-video-nouveau (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-nouveau in Ubuntu. https://bugs.launchpad.net/bugs/1580359 Title: Ubuntu INSTALLER will not start using nvidia card unless nomodeset is included in grub options To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/1580359/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp