I built a 4.0 kernel and booted Fedora 21 on it with x2go server on Fedora 

21 box. Accessed from Ubuntu 14.10 box. Tried a high definition Youtube video, worked okay not expanded to full screen. In full screen mode, it was mostly okay but sometimes with rapid panning there was some jerkiness. Sound was smooth either way. I was mostly just curious to see if the 4.0.0 kernel broke anything notable but on the server side seems okay.

  On the client side, my Nvidia drivers will not load with the 4.0 kernel

so couldn't really test client performance under that kernel.

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