External drive experiences

I took quite some time to play around with the external 360-drive hooked up to my console. I am running an unmodified original FW on the Hitachi drive. I took the PGR3 disc from the shelf after it's been collecting dust the last few months. And I gotta say: I love it again :)

Never had any problems playing until I downloaded the Style Pack and the Turbo Pack for PGR3. The problems started when I was playing one of the new type of games: "Cat and Mouse". The race would startup fine but after almost one round of driving the 360 would freeze and then reboot. I had the exact same thing with the "Team Cone Challenge" game.

All the other games (on- and offline), cars, tracks, challenges work fine using the external drive.

Since I wanted to get to the bottom of this I deceided it was time to hook up the drive directly to the console. The only difference in this situation is the power is coming from the 360-motherboard. I could play "Cat and Mouse" and "Team Cone Challenge" without a problem this way. Makes me really confused!

Any suggestions/comments would be welcome :)