https://bugs.freedesktop.org/show_bug.cgi?id=93826
--- Comment #14 from Damien dherault@hotmail.com --- Grub uses the old VGA driver and can not handle the 290x @144hz. It's the same issue with the opensource which works correctly only @60 Hz... I fixed the problem by forcing a resolution with grub.
But impossible to solve the issue with the xf86-video-ati driver. Also tried the git version.
Remember, no issue with windows & linux with Catalyst fglrx driver so I do not trust a hardware issue. There must be a différence in refresh rate management if catalyst wedge to 144Hz immediately after installation while the opensource driver made a bizarre 139Hz with artifacts (see attachments).
Can be an important point to clarify: I use DisplayPort 1.2.