Well, specification wise the 760GT would be roughly twice as fast as the 750GT. It has a 256 bit bus compared to 128 bit, many more GPU cores, the list goes on. In fact it is just a better card. The memory bandwidth alone would make it a faster card.
Geforce GTX 760 192256 MB/sec
GeForce GTX 750 Ti 86400 MB/sec
Still, as I said the 750 is a good card, and for £120 odd not a bad buy. It also uses a lot less power than a 760, so is a greener option! Not to mention not needing an expensive PSU to run it. The 760 card are min £150, and normally more like 170-180 so obviously are a bit more pricey.
Probably for pure performance an AMD card would be a better option, but I tend to avoid em. I've never owned one I was happy with in the past. Plus Blender needs Cuda to do realtime rendering and I would want that if I upgraded
I am torn at the moment whether to try to save for a 760, or buy my Brothers 580. The 580 is still faster than a 750 in all respects although the margins are slim in places. It would be vastly faster than what I have, but do I go for that power hungry card, or save for a slightly more efficient 760? Or do I try to save my energy bills by getting a 750, which will do the job and save lots more power? It's always a difficult decision when buying a new card, unless you are so loaded none of this concerns you! Price, power usage, performance all have to be considered. Don't do your homework, and you may get a shiny new card, fit it, and find the system just will not power, or the card is stuck in a low power setting. All because your PSU is not capable of powering it, meaning more cost, and waiting of course!
Anyway, that's my advice on video cards for the day lol. Hope it helps anyone considering an upgrade to consider all options
Edit
Quote: "This is one topic that confuses me as it would seem even if you have a crazy over powered cards for this type of thing you still get around the same fps like me for
example i get almost the same fps as most of you guys even with 2x Asus R9 Crossfire so who knows "
Well, once you go beyond a certain point there is no advantage to a faster card. Unless you up the resolution. It mostly makes a difference with High def and of course with 4K slowly coming in will make a huge difference with that. You would notice your faster cards still run at a good speed in higher res, but the slower cards would be falling away as you increase it. Fill rate is an important measure of a cards speed, and the more pixels you use the more relevant it is. So that is at least one of the reasons why