I have a 16GB class 2 card on my phone and it is god awful slow when the music app searches for songs after each reboot/desktop connection. I only have 1400 songs including a few gigs of FLAC files and it takes nearly 10 minutes for it to search all my songs.
My 9900 restarts if it hits a hard object (defect?) and the songs have to be researched again. This is extremely annoying while driving as my blackberry is the main music device. Would buying a class 10 micro sd help at all? I noticed the song search for better on the early OS releases but on .440 it's painfully slow as I described.
