I tried multiple free distros, with mixed results.

• Debian 9.9.0 (kernel 4.9.0-9-amd64)
• Trisquel 8.0 (kernel 4.4.0-119-generic)

• Debian 10.6.0 (kernel 4.19.0-11-amd64)

• Dragora 3.0-beta-1 (kernel 4.19.79-gnu)
• Hyperbola Milky Way v0.3.1 (kernel 4.9.210-gnu-1-lts)
• Parabola (kernels 5.1.6_gnu and 5.7.10)
• PureOS 9.0 (kernel 4.19.0-9-amd)

Internal wifi card does not work with free software.

Based on this Lenovo forum thread, it seems the G50-45's BIOS prevents unapproved wifi cards.

(Tested on live Trisquel 8.0, kernel 4.4.0-119-generic)

$ glxinfo | grep rendering
direct rendering: Yes

glxgears runs at about 295 FPS, and htop shows all 4 CPU cores spiking up to ~80% when using glxgears.

HDMI and VGA outputs do not work. Display settings show Monitor: Unknown and cannot change resolution from 1366x768. Brightness cannot be reduced from 100%. As the screen is very bright, this may present a major usability issue to some users, and it drains the battery quickly.

GPU/display performance is poor. Video playback (in VLC) is buggy and lags sometimes. The image is low-quality as it has too much pixelation. SuperTuxKart at lowest rendering settings runs far too slowly to be playable.

Internal Bluetooth card does not work.