From Microsoft blog:

Today we are releasing Windows 10 Insider Preview Build 10565 to Windows Insiders in the Fast ring. This build has quite a few new features and improvements so we’re really excited to get this one out to you for you to try out. One thing I want to call out up front is that this build and associated Language Packs won’t be available until later this week for Windows Insiders in Russia and Turkey.

Here’s what’s new in this build:

Compatible Operating Systems
AMD Catalyst™ 15.9 Beta is designed to support the following Microsoft Windows platforms:
Windows® 10 (32 & 64-bit)
Windows® 8.1 (32 & 64-bit)
Windows® 7 SP1 or higher (32 & 64-bit)

Highlights of AMD Catalyst™ 15.9 Beta Windows Driver

Performance Optimizations
Star Wars™: Battlefront Beta - Performance and quality optimizations
Fable Legends : Includes the latest DirectX® 12 optimizations for the Fable Legends: Benchmark

Straight from the Horses mouth:
Summary:
In addition to the changes that are listed for the vulnerabilities that are described in Microsoft Security Bulletin MS15-097, this security bulletin addresses a defense-in-depth update for the secdrv.sys driver, a third-party driver. The update turns off the service for the secdrv.sys driver. *****This may affect the ability to run some older games.*****
Microsoft has instruction on how to allow the DRM to run and how to disable the DRM when it's no longer required.

Windows 10 Insider Preview build 10547 is released on the fast ring.

Click here for Info.