Yesterday I noticed that some DVD's I've burned aren't being read by my MBP. These are DVD's I've burned on an PPC iMac. If I pop on of the DVD's into my folk's new MB the DVD's are read just fine. They never show up in my finder and there is not error message nothing happens. Applecare says that since my MBP reads at 6x and these DVD's *may* have been burned at 8x they are thus unreadable. I've been burning CD & DVD's for a long time now and I've never heard that a burn speed locks in the read speed and makes a DVD useless. Have I just been missing this absolutely huge thing? Or is there something else wrong with my optical drive?