Here is the problem. I have a WD6401AALS hard drive that passes smart and extended test. Fails quick test for some unknown error. I did advance RMA from WD and they sent me a WD7501AALS. My bios sets the 640 to LBA mode. It sets the 750 to CHS mode (its "recertified" and has an ungodly spin up count). Has anyone else ran into this? The CHS mode is a little unsettling to me. Should I be concerned??