Games running 50%

[Shonumi]

Your CPU is very weak for Dolphin actually. I would imagine that your CPU is throttling itself when you try to run Dolphin. Open the Windows Task Manager (or use CPU-Z if you prefer) and monitor your CPU's frequency as you play. While your hardware is lowend for Dolphin, I find it odd that all games hit ~50%, which sounds likes your clock frequency is being limited.