I7 dual or i7 quad?

What could be faster and better performance  i7 dual 2.9GHZ or i7 quad 2.6GHZ and explain why please?
What could be better for montaging, editing videos and for home studio recording? 
   Macbookpro 13 inch with i 7 dual 2.9 or macbookpro with retina15 inch  i7 quad 2.6GHZ   ?
i7 dual 2.9
Flash storage
Ram 8GB
i7 quad 2.6
Ram 8GB
flash storage


For clarification when I speak of "workload" I am refering to the amount of task being handled at one time by the cpu.  Increased workload being directly associated with multiple task being handled at one given time. 
The clock speed of the duel core cpu might be 2.9 ghz but it has to divide all task between only two cores.  Also the duel core has integrated graphics which means the gpu is the cpu in the case of the intel 4000hd graphics chip.  This is done by multi threading the bandwith of data over 8 threads of data traffic instead of two like in the intel 3000hd integrated graphics chip.  This allows the 4000hd to process faster but it's also sharing the 8 threads with normal cpu functions. 
Also the amount of memory the gpu side of the cpu will use is shared with the main system memory.  This taxes the system resources more becuase now you are given less main system memory while a dedicated amount of system memory is now being used for integrated graphics functions during task such as video compression or gaming. 
What may have started out as 4gb of main system memory turns into approximately 3.6gb of main system memory as 384mbs is seperately used only for graphics processes.  The amount of shared memory can not be changed so if you needed more your out of luck.  While handling the heavier graphics task however the cpu/gpu will turbo boost to the higher speeds (3.6ghz).
The same could be true with the quad core when memory is conserned but the quad core will switch over to the discrete graphics card (Nvidia) and offload all heavier graphics processes from the intel gpu to the nvidia gpu which also has more dedicated graphics memory which is faster and seperate from main system memory.  So the discrete graphics card will not only handle the heavier graphics related processing, but will also free up your main system memory.  Also the cpu will turbo boost to keep the system running more smoothly.
Heavier graphics task would include task such as video compression, movie editing, and gaming (Battlefield 3 for example.)