If you have difficulties with the choice of a processor, you will solve them by looking at comprehensive benchmark Intel Core i5-6600K Cinebench r23 score single and multi core and understand is it a good CPU or a bad one to buy, how powerful is this CPU. Here is all information from Cinebench r23 benchmark. A careful review of all the specifications, to make it easier to read, is made by the table. After looking at the data of parallel test and video, you can already make an briefed decision about do you need to buy Intel Core i5-6600K or not.
However, it should be understood that the summary data in the article above do not mean that taking them into account you should completely trust a simple quantitative comparison. Be sure to watch benchmarks video and read the opinion of real owners of Intel Core i5-6600K before deciding buy this CPU or not.