I saw on task manager that pc Using 9-10mbps when downloading from google drive, but when downloading from other sources it using only 2-3mbps. It's not only happening on pc but on every device, but maybe it is something with bandwidth.probably bandwidth issue on the server.
Remember that MB/s is Megabytes per second and mbps is Megabits per second. 8mbps equates to 1MB/s. So if your rated speed is 10mbps then you're looking at around 1.25MB/s download.