What about the K located at the end of the Core i5-7600K? That is a suffix Intel uses to show specific features the processors sport. It's worth noting if you're considering Intel's 7th-gen processors that they only support Windows 10. If you wish to go for the more capable CPUs, be sure to check the higher model numbers within a product line.
The Core i5-7 600K is more advanced than the i5-7 500, for example. The latter three digits determine the SKU and just how powerful the processor is within its immediate product line. Simply look at the first digit in a model number, and you'll be able to tell if it's a newer or older processor.
Taking the examples above, the Core i5- 6400 is sixth generation, while the i5- 7600K is part of the most recent, seventh-gen. It's actually really easy to determine the generation a particular processor belongs to.
