Known issues with the current DirectX plugin, download an older revision with the older DirectX video plugin or use the OpenGL plugin if your computer can handle it.
Generally any revision prior to 3545 or 357x and the DirectX plugin from around the 2xxx revisions is fine. Just to inform you, the DirectX plugin is quite buggy and contains a lot of graphical issues that were fixed in the OpenGL plugin. It also might not solve the graphical problems you are experiencing.
The developers primary focus seems to be on the OpenGL plugin, the DirectX plugin has not received any updates or fixes for over a thousand revisions now if you exclude the minor fix that was applied when the plugin specifications changed.
As to why their focus is on OpenGL, my guess is because it is multi-platform and easier to work with, where DirectX is tied to Windows only.
Also your processor is quite weak, don't expect very good frame rates or speed in Dolphin.
Generally any revision prior to 3545 or 357x and the DirectX plugin from around the 2xxx revisions is fine. Just to inform you, the DirectX plugin is quite buggy and contains a lot of graphical issues that were fixed in the OpenGL plugin. It also might not solve the graphical problems you are experiencing.
The developers primary focus seems to be on the OpenGL plugin, the DirectX plugin has not received any updates or fixes for over a thousand revisions now if you exclude the minor fix that was applied when the plugin specifications changed.
As to why their focus is on OpenGL, my guess is because it is multi-platform and easier to work with, where DirectX is tied to Windows only.
Also your processor is quite weak, don't expect very good frame rates or speed in Dolphin.