In Asia, a video review leaked of the Core i5-10400, and that would be Comet Lake. Interesting to see is that the Core i5-10400 is lined up against a Core i7-9700F, the results show that both processors are pretty close towards each other in performance.

The review is based upon synthetic benchmarks one, the i5-10400 is listed being an engineering sample. Cinebench R15 (single) scores 186 points which makes it sit between the i5-9400F and i7-9700F. For the multi-threaded run hyperthreading obviously helps and scores 1,351 points. These numbers, however, are not enough to tackle Ryzen 5 3600.

In 3DMark Firestrike things look pretty for the 10400, as it's faster than a core i7-9700F. The review also covers two games, GTA V and Assassin's Creed Odyssey. In these titles, the i5-10400 does well, passing the i7. 

Core i5-10400 Benchmarks Shows performance close to i7-9700F