Intel Broadwell Iris Pro Graphics: Windows 10 vs. Linux
When increasing the image quality settings for Xonotic to "high" at 1080p, the Core i7 5775C graphics were just shy of 10% faster under Windows 10 than Fedora 22 with the updated drivers. Of course, under Linux the game is still very much playable with the latest-generation Intel graphics.
When increasing the Xonotic image quality settings to their ultra and ultimate pre-sets, Windows 10 with the latest Intel proprietary driver was still in the lead over the open-source Intel Mesa driver code by 10~20% for this popular open-source game.