It's simple. The dingoo A320 has a internal, single-cored JZ4740 CPU with 400Mhz stock clock (running at 336 default) and NO GPU AT ALL.
The Sony PSP has a 333Mhz MIPS, single-cored CPU, backed up by a nVidia GPU.
To emulate a console, handheld, device, (put name of electronic equipmente here), you need at least 3x Times the processing power of the emulated device.
If you dont know what a GPU is:
A GPU is a chip/processor created especifically and unically for graphics and physics processing. If a device lacks such a thing, like the A320, then generating 3D graphics is a hard and slow task.
What's more, a 2D game CAN ALWAYS
(or not) use special effects that ONLY A GPU CAN PROCESS OR CREATE.
For example: Blur (can be done by processor, slow), Shadows (Slow on CPU too), Shading (Pixel Shader, cant be done by processor), Vertex shading (same as PixelShader), Water reflections (hardly done by processor).
Did you get? I'm not explaining that again.