It's not as simple as that. Memory is required above all on GPU to accomodate for: higher resolution textures, anti-aliasing and screen resolution itself.
That means if you are playing on 1080p it's quite possible there's idle gDDR memory on your card and increasing it would make absolutely no difference. With a GTX1060 having 6GDDR you can't go out of memory on 1080p gaming.
Of course, a higher end card features higher memory clocks, core clock and other stuff beoynd my field of knowledge but it's good to have in mind when buying one you'll pay for resources not needed.
Syndicate might not be a new release but it's a gorgeous game on pc and it takes less than 4GB of vRAM to run on max settings 1080p.
Intel's branding on the Corei# family has the terrible confusion of not explicitely saying these are like the NVidias card endings in 50, 60, 70 or 80. I'm not really up to date on this but there are a number of different generations on intel's processors and a new Corei5 bought today is like a GTX1070 while an old Corei5 could be a GTX670. Corei7 are like SLIs of video cards: never actually needed if you're not trying to simply game and the cost benefit is way lower.
There has never been any need to buy an i7 to prevent bottlenecking on a single graphic card.
Just make sure your processor has a nice core clock speed and is a current generation model. Processors used to be really important from the Pentium Dual core to Core 2 Duo and Core 2 Quad era but since the corei family intel produced these insanely potent CPUs and gaming was never capable of taking advantage of so much logic processing.
Fun fact: the x360 and ps3 era was specially troubling for consoles and the highest gap in PC vs console looks I witnessed because when they were being developed CPU power was very important in gaming and so both Microsoft and Sony spent a big budget developing a super CPU, especially the crazy ps3 processor "Cell".
Not so long after both consoles launch turned out video cards developed A LOT and PCs having the advantage to upgrade as soon as tecnology is avaible gained an abyss of a distance from that console generation hardware power. The playstation 3 had a 256mb video card and the x360 had 512mb while PCs shortly after could aford without paying much 2GB IIRC. Which at the time was actually a big deal becuase as I've shown above, 1080p can actually go beoynd this amount of needed vram (of course not 3GB like today's games).