Another (simpler) way to benchmark the performance of your flash memory stick is to use the 'dd' command to make a backup copy of the entire disk.
Where: '/dev/sdb' is your flash device, (use GParted or 'sudo fdisk -lu' to find out).
sudo dd if=/dev/sdb of=/home/herman/usb.backup bs=4096 conv=notrunc,noerror
You will see that the dd command will show you the speed the operation was performaed at. That might not necessarily be an indication of the flash memory's speed though, but an indication of the speed of the slowest link in the process. (possibly the USB1 interface, or the speed of your hard disk or something).
At the same time, you will be making a backup of your USB, so you can erase it in order to use bonnie++, (if you want to).
974927+1 records in
974927+1 records out
3993304576 bytes (4.0 GB) copied, 391.608 s, 10.2 MB/s
To restore your flash memory again after you're finished,
I won't have time right now to explain how to use bonnie++, but I'll be back later.
sudo dd if=/home/herman/usb.backupe of=/dev/sdb bs=4096 conv=notrunc,noerror