Perhaps you can't decide which CPU to buy, you can make a decision after reading the full test Intel Core i7-7900X Cinebench r20 score single and multi core and decide is it a good CPU or a bad one to buy, how powerful is this processor. Here you can find all information from Cinebench r20 benchmark. A careful analysis of all the technical characteristics, so that it can be easier to read, is made by the table. After looking at the data of joint test and video, you can already make an informed decision about do you need to buy Intel Core i7-7900X or not.
However, it should be realized that all the data in the text above do not mean that taking them into account you should undividedly trust a simple comparison of these numbers. Better to watch the video tests and read the opinion of real owners of Intel Core i7-7900X before deciding buy this processor or not.