Thank you for contacting Intel Embedded Community.
We are working to give you an update as soon as possible.
Thanks in advance for your patience and understanding.
Tools for checking hardware acceleration might vary depending on the code that you are using, one rough way to test if your platform supports HW acceleration is to install comercial tools that use HW accel and check if the acceleration can be enabled. For example VLC, Firefox, PowerDVD can enable HW accel.
There is also the DXDiag tool that might indicate if DirectDraw Acceleration and Direct3D Acceleration is enabled.
The DirectX have some sample applications that might be useful for you ddex1.exe ddex2.exe, tec.
What I can suggest for your application is to try with an Intel® Tunnel Creek platform, or with a fresh vendor supplied unit that you could start a new test.
Using the document User Guide: Intel® EMGD v1.15 and not modifying the BSP and following the instructions and using the recommended versions of MicroSoft, and check if you still have the performance problem.