Interesting, if you have been playing around with the preview build of Windows 10, then you will have noticed that after you updated it to the latest build it now has DirectX 12 support. If you look at the screenshot below, you can see that it is enabled in the OS itself.

Now unfortunately there are no further drivers let alone software to test DX12. You will need a DX12 GPU (for all DX12 features), a DX12 Driver and then a game or benchmark that has DX12 support. 

DX12 will add a lot of new features, but the most important one is significantly reducing overhead, much like Mantle making it dar more CPU friendly. BTW to make it clear, the biggest imporvement is reducing CPU overhead, you will need DX12 for that, but a DX12 GPU for that is not needed. The codebase simply is different and you will reap the benefits here even with a DX11 GPU.

If you like to give the Windows 10 preview build a try:

Microsoft has released another Windows 10 build for the Windows Insider program and this release brings with it a plethora of new features including Cortana, Continuum and a bunch more. To upgrade to the new build, follow the steps with your install of Windows 10 9879 or you can download the ISOs using the links at the bottom of this post.

- Click on the start menu and in the search box type 'Windows Update'
- Chose 'Windows Update Settings'
- In the left panel click 'Preview Builds'
- Click on the 'Check' now.
- Download the new build 

After you do this, if there are bits to download for your machine, the process will start and then the waiting game begins.

Download: Windows 10 9926 English: x86 | x64