yea, i5 dont have threads are raw cores, when i saw an i7 by the first time i tought that i would have 18 cores in a 980x you know C6/T12, hehe but it was a mistake of mine, pc regconies it like 12 cores, threads i think is like the video i saw once to fill two cups using one jar.
How do you define a full core? A Core i5 isn't like four single core CPUs packed together, they do share things like L3 cache, the memory controller and other IO and at least the PCIE controller. AMD CPUs share a bit more but the definition of a "full core" is arbitrary.
Honestly, the numbers of cores or how they are architected is as irrelevant as the clock speed for determining performance. You just have to run the benchmarks. So I am not sure why the question is relevant.