If I got anything wrong or explained it wrong please let me know.
CPUs these days usually have 2 or 4 cores,and the motherboard recognizes all the physical cores individually, thus, that is why it shows multiple cores. With i3, i5 and pentinum cpus which don't have hyperthreading, it just displays all the physical cores. With i7 and Xeon CPUs, with hyperthreading(extra "virtual" cores, they have one extra virtual core for every physical core, so quad core cpu will have 8 cores total). Hyperthreading is quite useful in cpu heavy applications or processes, but don't think that it will provide a huge increase in games. Games are becoming more CPU dependent but it will still tak quite a while for hyperthreading to really help with performance in game(it negatively affects performance in some games like AW for example). If it only displays 2 or 4 cores then it does not have hyperthreading as it would display the extra virtual cores.