xserver/gnome on external monitors extremely slow
I installed Fedora (Workstation Build) on my Thinkpad two days ago, since my Arch couldn't handle external monitors. On this point it's important to say the laptop has both Intel graphics and a nvidia card which (under Windows) can be used with nvidia optimus.
The internal monitor (which works without any flaws) is connected to both cards, while all external monitors are only connected to the nvidia.
External displays work, but the rendering on them is extremely slow, except when they are a mirror of the internal screen. The problem exists both with the internal monitor turned off and with the external monitor running as secondary display (also the other way round: external primary, internal secondary). This does not impact on the performance of the internal monitor.
(extremely slow meaning glxgears runs with 1FPs on external, 60FPs on internal)
I have not altered any drivers so far (both intel and nouveau driver are installed) and haven't installed any software that could interfere with the drivers
Hardware: Thinkpad W530
- i7-3720QM (4x2.60 GHz)
- 16 GB DDR3 RAM
- Intel HD Graphics 4000
- NVIDIA Quadro K1000M
- Fedora 23
Are there any error messages in your syslog? try running
dmesgandjournalctl -bfrom any terminal. There probably is an issue with hybrid graphics which hasn't been working well in Linux since it was introduced. Have you checked https://wiki.archlinux.org/index.php/... and https://wiki.archlinux.org/index.php/... ? They should mostly apply to Fedora too.