說準確一點就是

480Mbps = 480,000,000bit/s = 480,000,000/8/1024/1024 = 57.22MByte/s

1 Kbit/s =1,000 bit/s
1 Mbit/s=1,000,000 bit/s
1 Gbit/s=1,000,000,000 bit/s

注意看一下單位、大小寫