The .NET Framework 4.6 introduces the .NET Framework 4.6 Preview and .NET Core. Some new features apply to both, and other features are specific to .NET Framework 4.6 Preview or .NET Core.
1. ASP .NET 5
.NET Framework 4.6 includes, ASP.NET 5, which is a lean .NET platform for building modern cloud-based apps. The platform is modular so you can include only those features that are needed in your application. It can be hosted on IIS or self-hosted in a custom process, and you can run apps with different versions of the framework on the same server. It includes a new environment configuration system that is designed for cloud deployment. MVC, Web API, and Web Pages are unified into a single framework called MVC 6. You build ASP.NET 5 apps through the new tools in Visual Studio 14. Your existing applications will work on the new .NET framework; however to build an app that uses MVC 6 or SignalR 3, you must use the project system in Visual Studio 14.
2. 64-bit JIT Compiler
The .NET Framework 4.6 features a new version of the 64-bit JIT compiler. This compiler provides significant performance improvements over the existing 64-bit JIT compiler.
3. Improvements to event tracing
A .NET Framework 4.6 Preview EventSource object can now be constructed directly and you can call one of the Write methods to emit a self-describing event.
4. Resizing in Windows Forms controls.
This feature has been expanded in .NET Framework 4.6 Preview to include the DomainUpDown, NumericUpDown, DataGridViewComboBoxColumn, DataGridViewColum and ToolStripSplitColumn types and the rectangle specified by the Bounds property used when drawing a UITypeEditor.
Windows Store apps that target .NET Core and are written in C# can now take advantage of a new technology that compiles apps to native code rather than IL. They produce apps characterized by faster startup and execution times.