You haven't explained exactly how much time is "to[o] much time" for the copying to take. However assuming that your expectations are realistic (which needs to be confirmed), then you have a choice of several different approaches which you can use, depending on your skill, available equipment, time, budget, etc. I have mentioned some which are applicable to your situation, in this other thread:
wdc-wd7500aads-00m2b0-t22226.htmlFor example: Checking SMART data on both disks for any obvious abnormalities; moving one of your disks to another system and repeating your test, to see if the slowness moves with that disk; and using benchmark utilities to check the read (and perhaps write) performance of each disk independently.
If you have Linux skills, then using /dev/null & /dev/zero as appropriate can make it easy to get some quick benchmarking data for the separate disks.
It may help to better understand the cause of your problem if you explain more about the history e.g. has there always been a performance problem copying from this USB disk to internal disk, or is this a new problem? Have you already tried when using a different USB disk, or tried moving this USB disk to another PC and testing again? What other testing have you done, and with what results?