I have an USB3 HD (Lacie P'9230) that both HD Tune and Crystal Disk Mark measure to around 100 MB/s read speed.
I also have an USB 3 thumb drive (Flash Voyager) that Crystal Disk Mark measures around 33 MB/s write speed.
When I copy a folder with videos from the HD to the thumb drive, W7x64 shows me the speed totaling 6 MB/s.
What could sink the speed so low, compared to the measurements? Any ideas how to deal with this?