https://bugs.freedesktop.org/show_bug.cgi?id=69675
--- Comment #28 from Alex Deucher agd5f@yahoo.com --- Created attachment 88450 --> https://bugs.freedesktop.org/attachment.cgi?id=88450&action=edit use fractional fb div on DCE4+
Does this patch help? This should allow the pll value to more closely match the actual requested clock.