I have some BladeCenter HS20 blades with Qlogic HBA's that are hanging for nearly 15 minutes (literally!) at the Windows boot up. This is happening when plugged into a 3850 fabric. When you yank the fibre channel connection from the switch it boots normally. I also tried connecting directly to my Hitachi 9507V via local loop (bypassing the Brocade) which also boots normally. But when I plug it back into the 3850 it hangs again.