Microsoft had a Windows 10 preview event this week, where they made several interesting announcements. The main one is the one-year period, in which all current owners of Windows 7 and Windows 8.1 will be able to upgrade to Windows 10 for free. Based on December 2014 Steam hardware survey, 89% of Steam users will be able to upgrade their OS to Win 10 without paying a penny. Depending on the quality of Win 10 at release, this may lead to a very fast adoption rates, encouraging developers to use new APIs introduced in Windows 10.

The most important of those new APIs for gamers is DirectX 12, which will only be available on Windows 10. While there were rumours, they turned out too optimistic, but we got a free upgrade option instead. The main promise of DirectX 12 is the ability to access PC resources on lower level, thus reducing CPU overhead. Quite importantly, this feature will be supported on most existing DX11 GPUs. There will be also new graphical features in DX12 and DX11.3, requiring new hardware. Nvidia claims that their latest 2nd generation Maxwell GPUs already support all new features, but it may still change depending on what Microsoft will include in the final release.

There will also be a new Modern UI Xbox app for Windows 10. From its initial description, it seems like a replacement for Games for Windows Live, probably without game integration. Xbox app provides cross-platform chat and audio, as well as the ability to stream games from Xbox One to PC. While such functionality may not be very useful for gaming PCs, it may be more practical for tablets and weaker laptops.

Finally there is a very interesting new hardware from Microsoft – HoloLens. It is an augmented reality device, which merges virtual objects with real world. It is different from virtual reality (like Oculus Rift), where you are shown a completely virtual world. The technical details are very sparse at the moment, but several journalists got a fist-hand experience with the prototypes. While Microsoft advertisements showcases light cordless devices, HoloLens currently exist as much clunkier wired, but fully functional development kits. Unlike Oculus, HoloLens does not block your view, allowing you to see everything around you. The virtual images are only shown in a narrower central part of your field of view. These virtual images are quite sharp, translucent and visually seem to appear correctly in 3D space. There is a movement detection and virtual images respond to head movements with very low latency. HoloLens seems to be a very interesting product and may become a thing to get if Microsoft manages to achieve the vision of the device they show in ads without sacrificing its technical capabilities.