I think your answers are steeped with technical jargons that don't specifically address the question. The only relevant answers seem to be related to caching/compression algorithms that cannot predict random encrypted data. The rest seem to be gobbledygook, but I'll leave with that question...
The encryption/decryption is done within the CPU for USB flash drive without native encryption. Why would the flash controller and bus be the limiting factors? Wouldn't those be limiting factors even without Bitlocker encryption/decryption?
Can you be more specific about what is hardware encryption support?
Do you know, in percentage, the performance impact of Bitlocker on the drive througput?