I deleted the spam and read your last post....
I think we have seen the problem.
Which drivers should the Express Duo use? Microsoft or Super Talent.
The 2 drives are using different drivers, one is using Microsoft drivers and the other is using Super Talent.
The slower drive is using Super Talent and is installing as a SCSI Disk Device.
The faster drive is using Microsoft drivers and is installing as a USB Mass Storage Device.
I own and previously installed drivers for a SuperCrypt, This appears to be where the drivers for the slower driver are coming from.
They should both be using the Microsoft drivers.
The SuperCrypt drivers should not be used for the Express DUO (it will make it slow).
This is also why the capacities are different - different pervisioning for different formats.
NTFS will format out to a different capacity than FAT32, etc.
Try formatting it as FAT32 - good peformance, compatibility and good for a removable device.
Let me know. I will be checking back.