Hi Fabrice,
The issues that you are experiencing with your laptop are because it is below the minimum hardware requirements. 2 core processors have to be greater than 2.5GHz ( Intel only Sandy Bridge or newer). That will only bring it up to minimum, which will still be very slow to compile shaders, but it will allow you to launch the editor.
Running in DX10 will be significantly slower to compile shaders and some lighting may appear different. It will also cause the compiling of sub-menu shaders to be slower, making their recompiling more noticeable.
For a better editor experience, consult your Rocket Beta Orientation for the recommended system requirements. If you have any more questions, comments or concerns, please let us know.
Thank you,
Alexander