Significant improvements to the Garbage Collector (GC) and startup times, especially for Windows Store apps.
The 4.5 release was a significant "in-place" update to version 4.0, introducing several performance and developer-centric improvements: download net framework 4.5
Updates to ASP.NET and WCF (Windows Communication Foundation) for more efficient web service management. System Requirements Significant improvements to the Garbage Collector (GC) and