GTX 765M i7 vs GTX 770M i5

for gaming the i7.. its a quad core. the i5 is a dual core

The hell, where did you get that from both are Quad Core but i7 has Hyper-Treading enabled (Octa-Tread). This is half true for Ultrabooks as they all have dual cores, but even then they all have Hyper Threading (including the i5, I think the only difference is L3 cache and possibly higher clock speeds).

youre thinking about desktop cpus. i5 on laptops are dual cores. even some i7 on laptops are dual cores too.

http/ark.intel.com/products/76348/Intel-Core-i5-4200M-Processor-3M-Cache-up-to-3_10-GHz
http/www.notebookcheck.net/Intel-Core-i5-4200M-Notebook-Processor.93558.0.html

As I said it depends on the Device, all ultrabooks have 2 physical cores, not ALL i5's are Dual Core, some higher end i5 laptops have Quad.
EDIT: There is no i5 quad-cores on mobile. But I still recommend it for every game except for games like minecraft and Arma 2

thats wrong. all i5 on laptops are dual cores unless someone decides to put a desktop cpu in to a laptop.

http/ark.intel.com/products/family/75024
http/ark.intel.com/products/family/65504/3rd-Generation-Intel-Core-i5-Processors/mobile
http/ark.intel.com/products/family/59134/2nd-Generation-Intel-Core-i5-Processors/mobile

Whats the price difference between the two?

Seeing what you want to use them for, if the I7/765m is much cheaper I would just go with that. I have that combo and am able to play games like Bf4 on High (on 1080p) without problems and the temps dont hit above 63C for the GPU (I wish I could say the same thing about the i7, as it tends to heat up way to much hence why I have it underclocked to keep temps down, which has helped very much, of course your particular model might have better cooling for i7).

When it first was released the 765 was getting some bad fps in games but I heard that new drivers would fix this problem, it seems they were right (also due to low temps you can overclock 765M, though I dont recommend that unless you know exactly what you are doing)

Though as others have said the GTX 770M is a pretty big jump over a 765M, so its really a question of what kind of performance you want since either can play the games you want to. And if you want best of both worlds (great GPU and CPU) then just upgrade from i5 4200M to an i7 4700MQ on the laptop with 770M