Intel Processors

i7 at the fastest and have the most cores and hyper-threading enabled. Hyper-threading essentially makes two cores out of one by interleaving two process threads in a core to reduce any down time. There are two types of i7...standard and enthusiast. Standard will have 4 cores along with an integrated GPU and enthusiast will have 6 or 8 cores and no GPU. Integrated GPUs so far have had minimal impact if you're using a discrete NVIDIA or AMD GPU, but DirectX 12 is going to make more use of them with asynchronous compute capabilities. You can also do things like offload streaming encoding to them if you stream while gaming.

i5 will be like the i7 except without hyper-threading and possibly a lower clock speed. i3 will drop down to 2 cores but regain the hyper-threading as see a drop in the clock speed, too. There is Pentium below that, too.

For the numbers, the first is the generation of chip (although the generation number on the enthusiast chips is 1 higher that it really should be). The second number is the series: 8 and 9 for the enthusiast chips, 7 for the i7, 4 through 6 for the i5, and 1 through 3 for i3; the higher the number the better the bin. The last two numbers represent the bin of the chips in the series, the higher ones will have a higher clock speed for the rated power. The letter on the end represents the power. X and K will be the unlocked chips you can overclock. No letter will be the standard chip. S is a low power chip. T is an ultra-low power chip.

You can browse through all of the chips at ark.intel.com.

Yes, no-name, that was a good answer.

Frank