Let's say you can't decide which CPU to buy, you can make a decision after reading the comprehensive test Intel Core i7-5820K Cinebench r20 score single and multi core and understand how powerful is this processor, is it a good processor or a bad one to buy. Here you can find useful information from Cinebench r20 benchmark. A step-by-step analysis of all the technical characteristics, to make it easier to understand, is made by the table. After looking at the data of all test and video, you can already make an informed decision about do you need to buy Intel Core i7-5820K or not.
Although it should be realized that all the data in the text above do not mean that you should be guided entirely by them and trust a simple quantitative comparison. Better to watch benchmarks video and read the opinion of of people who bought Intel Core i7-5820K before making a choice buy this processor or not.