Mám dojem, že niektoré OS nastavujú USB disky defaultne na "optimized for quick removal" - čo neskutočne spomaľuje prenos...
Že sa to deje "iba" pri NTFS nestuším..., ale možno by stálo za pokus zmeniť nastavenia USB disku na "optimize for performance":

To optimize your USB drive for performance:

1. Right click on the USB drive and select properties
2. Select the Hardware tab
3. Under All Disk Drives, highlight your USB drive and select Properties
4. Select the Policies tab and select Optimize for performance.
5. Press OK twice, and your transfer speeds should increase dramatically