Specifically, a weights file for YOLO v5 is 27 megabytes. Our weights file for YOLO v4 (with Darknet architecture) is 244 megabytes. YOLO v5 is nearly 90 percent smaller than YOLO v4.” So, it said to be that YOLO v5 is extremely fast and lightweight than YOLO v4, while the accuracy is on par with the YOLO v4 benchmark.