Windows from usb very slow


I’ve cloned a bootcamp partition from my mac mini to a Pendrive (usb 3.1)(HyperX savage 350 mb/s read and 250 mb/s write speed) and i’ve made a same clone to my old external Samsung hdd (usb 2.0). The usb pen drive is very-very slow during the boot and during the working too. The Samsung drive is much faster…
Can you help me why is happening?

Thank you

Can you open up Activity Viewer and see what kind of speeds you get when copying other types of files?