clarification about Deferred rendering vs Forward rendering on vita

i m working on a horror game for the vita and the rendering technique is very important for me to make a better atmosphere for my game but when i set up my build into deferred the frame rate goes down to less than 10 frames per second but when i set it up to forward i got to between 80 frames and 30 frames ... i want to ask does the vita not strong enough to handle deferred rendering ? i thought deferred rendering is better in terms of framerate


any help or suggestion will be great

 

Deferred lighting is more bandwidth demanding as it requires larger buffers and more memory transfers. It also requires a z-prepass (in the case of the Unity approach which doesn't use a full g-buffer prior to V5) for platforms without MRT. The only advantage is it only shades visible pixels and becomes effectively more efficient with a large number of dynamic lights. On weaker platforms, such as mobiles, were you would typically use backed lighting, forward rendering would be much faster. Forward can be very efficient especially in combination with good visibility culling.
Because of its limited performances, dynamic lights is something you want to avoid as much as possible on the vita anyways. Also the vita has a hardware deferred rendering pipeline, which means it only shades pixels once because it performs visibility culling for triangles beforehand. It stores vertex attributes in a buffer and performs shading afterwards. So there is little point in using software deferred rendering, you just will waste time doing in software what the hardware already does.