Cruzer 16gb issues w/ xbox 360

I just installed a 16gb cruzer flash drive as a quick fix for a bad hard drive, seems to work, however, the following msg appeared,

I’m getting a "Performance Warning” message, what does that mean?
If your device doesn’t meet Xbox 360 performance recommendations, you may experience significant performance problems playing games from the device or saving games and profiles to it. Buy an Xbox 360-branded USB Flash Drive to ensure optimal performance. More info"

It’s a Sandisk drive and sandisk makes the xbox labeled drive, so why would this show up?

yes, both are made by sandisk but the xbox drive is a higher performance drive tuned and formatted specifically for  use in the xbox. That being said i have used drives that say they do not meet the performance specs and i have not experienced any issues. is installing a game is slow? sure, but no significant issues that interrupted play.